diff --git a/core/modules/responsive_preview/lib/Drupal/responsive_preview/Plugin/Core/Entity/Device.php b/core/modules/responsive_preview/lib/Drupal/responsive_preview/Plugin/Core/Entity/Device.php
new file mode 100644
index 0000000..c641da3
--- /dev/null
+++ b/core/modules/responsive_preview/lib/Drupal/responsive_preview/Plugin/Core/Entity/Device.php
@@ -0,0 +1,96 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\responsive_preview\Plugin\Core\Entity\Device.
+ */
+
+namespace Drupal\responsive_preview\Plugin\Core\Entity;
+
+use Drupal\Core\Entity\Annotation\EntityType;
+use Drupal\Core\Annotation\Translation;
+use Drupal\Core\Config\Entity\ConfigEntityBase;
+
+/**
+ * Defines the responsive preview device entity class.
+ *
+ * @EntityType(
+ *   id = "responsive_preview_device",
+ *   label = @Translation("Responsive preview device"),
+ *   module = "responsive_preview",
+ *   controllers = {
+ *     "storage" = "Drupal\Core\Config\Entity\ConfigStorageController",
+ *     "list" = "Drupal\responsive_preview\DeviceListController",
+ *     "form" = {
+ *       "default" = "Drupal\responsive_preview\DeviceFormController"
+ *     }
+ *   },
+ *   config_prefix = "responsive_preview.device",
+ *   entity_keys = {
+ *     "id" = "id",
+ *     "uuid" = "uuid",
+ *     "label" = "label"
+ *   }
+ * )
+ */
+class Device extends ConfigEntityBase {
+
+  /**
+   * The machine name of this device.
+   *
+   * @var string
+   */
+  public $id;
+
+  /**
+   * The UUID of this device.
+   *
+   * @var string
+   */
+  public $uuid;
+
+  /**
+   * The human-readable label of this device.
+   *
+   * @var string
+   */
+  public $label;
+
+  /**
+   * The weight of this device in listings.
+   *
+   * @var int
+   */
+  public $weight;
+
+  /**
+   * Default orientation.
+   *
+   * @var string
+   *   Either 'landscape' or 'portrait'.
+   */
+  public $orientation;
+
+  /**
+   * Dimension information.
+   *
+   * @var array
+   *   Associative array with keys 'weight' (int), 'height' (int)
+   *   and 'dppx' (int).
+   */
+  public $dimensions;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function uri() {
+    return array(
+      'path' => 'admin/config/content/responsive_preview/manage/' . $this->id(),
+      'options' => array(
+        'entity_type' => $this->entityType,
+        'entity' => $this,
+      ),
+    );
+  }
+
+}
diff --git a/core/modules/responsive_preview/lib/Drupal/responsive_preview/DeviceFormController.php b/core/modules/responsive_preview/lib/Drupal/responsive_preview/DeviceFormController.php
new file mode 100644
index 0000000..b2badea
--- /dev/null
+++ b/core/modules/responsive_preview/lib/Drupal/responsive_preview/DeviceFormController.php
@@ -0,0 +1,118 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\responsive_preview\DeviceFormController.
+ */
+
+namespace Drupal\responsive_preview;
+
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Entity\EntityFormController;
+
+/**
+ * Form controller for the device entity edit forms.
+ */
+class DeviceFormController extends EntityFormController {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function form(array $form, array &$form_state) {
+    $entity = $this->entity;
+    $form['label'] = array(
+      '#type' => 'textfield',
+      '#title' => t('Device name'),
+      '#default_value' => $entity->label(),
+      '#size' => 30,
+      '#required' => TRUE,
+      '#maxlength' => 64,
+      '#description' => t('The name for this device. Example: "Small", "Medium", "HTC One", "Google Glass", "Smart TV".'),
+    );
+    $form['id'] = array(
+      '#type' => 'machine_name',
+      '#default_value' => $entity->id(),
+      '#required' => TRUE,
+      '#disabled' => !$entity->isNew(),
+      '#size' => 30,
+      '#maxlength' => 64,
+      '#machine_name' => array(
+        'exists' => 'responsive_preview_device_load',
+      ),
+    );
+    $dimensions = $entity->get('dimensions');
+    $form['dimensions'] = array(
+      '#type' => 'details',
+      '#title' => t('Dimensions'),
+      '#tree' => TRUE,
+    );
+    $form['dimensions']['width'] = array(
+      '#type' => 'textfield',
+      '#title' => t('Width'),
+      '#default_value' => $dimensions['width'],
+      '#field_suffix' => 'px',
+      '#size' => 6,
+      '#required' => TRUE,
+    );
+    $form['dimensions']['height'] = array(
+      '#type' => 'textfield',
+      '#title' => t('Height'),
+      '#default_value' => $dimensions['height'],
+      '#field_suffix' => 'px',
+      '#size' => 6,
+      '#required' => TRUE,
+    );
+    $form['dimensions']['dppx'] = array(
+      '#type' => 'textfield',
+      '#title' => t('Dots per pixel (dppx)'),
+      '#default_value' => $dimensions['dppx'],
+      '#size' => 4,
+      '#required' => TRUE,
+    );
+    $form['orientation'] = array(
+      '#type' => 'select',
+      '#title' => t('Default orientation'),
+      '#default_value' => $entity->get('orientation'),
+      '#options' => array('portrait' => t('Portrait'), 'landscape' => t('Landscape')),
+    );
+    $form['status'] = array(
+      '#type' => 'checkbox',
+      '#title' => t('Show in preview list'),
+      '#default_value' => $entity->get('status'),
+    );
+    $form['weight'] = array(
+      '#type' => 'value',
+      '#value' => $entity->get('weight'),
+    );
+
+    return parent::form($form, $form_state, $entity);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function save(array $form, array &$form_state) {
+    $entity = $this->entity;
+
+    // Prevent leading and trailing spaces in device names.
+    $entity->set('label', trim($entity->label()));
+    $uri = $entity->uri();
+    if ($entity->save() == SAVED_UPDATED) {
+      drupal_set_message(t('Device %label has been updated.', array('%label' => $entity->label())));
+      watchdog('responsive_preview', 'Device %label has been updated.', array('%label' => $entity->label()), WATCHDOG_NOTICE, l(t('Edit'), $uri['path']));
+    }
+    else {
+      drupal_set_message(t('Device %label has been added.', array('%label' => $entity->label())));
+      watchdog('responsive_preview', 'Device %label has been added.', array('%label' => $entity->label()), WATCHDOG_NOTICE, l(t('Edit'), $uri['path']));
+    }
+    $form_state['redirect'] = 'admin/config/content/responsive_preview';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function delete(array $form, array &$form_state) {
+    $form_state['redirect'] = 'admin/config/content/responsive_preview/manage/' . $this->entity->id() . '/delete';
+  }
+
+}
diff --git a/core/modules/responsive_preview/lib/Drupal/responsive_preview/DeviceInterface.php b/core/modules/responsive_preview/lib/Drupal/responsive_preview/DeviceInterface.php
new file mode 100644
index 0000000..7b01572
--- /dev/null
+++ b/core/modules/responsive_preview/lib/Drupal/responsive_preview/DeviceInterface.php
@@ -0,0 +1,17 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\responsive_preview\DeviceInterface.
+ */
+
+namespace Drupal\responsive_preview;
+
+use Drupal\Core\Config\Entity\ConfigEntityInterface;
+
+/**
+ * Provides an interface defining a device entity.
+ */
+interface DeviceInterface extends ConfigEntityInterface {
+
+}
diff --git a/core/modules/responsive_preview/lib/Drupal/responsive_preview/DeviceListController.php b/core/modules/responsive_preview/lib/Drupal/responsive_preview/DeviceListController.php
new file mode 100644
index 0000000..ab76894
--- /dev/null
+++ b/core/modules/responsive_preview/lib/Drupal/responsive_preview/DeviceListController.php
@@ -0,0 +1,138 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\responsive_preview\DeviceListController.
+ */
+
+namespace Drupal\responsive_preview;
+
+use Drupal\Core\Config\Entity\ConfigEntityListController;
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Form\FormInterface;
+
+/**
+ * Provides a listing of responsive preview devices.
+ */
+class DeviceListController extends ConfigEntityListController implements FormInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormID() {
+    return 'responsive_preview_admin_devices_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildHeader() {
+    $row = parent::buildHeader();
+    unset($row['operations']);
+    $row['label'] = t('Name');
+    $row['dimensions'] = t('Dimensions');
+    $row['orientation'] = t('Default orientation');
+    $row['status'] = t('Show in list');
+    unset($row['id']);
+    $row['weight'] = t('Weight');
+    $row['operations'] = t('Operations');
+    return $row;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildRow(EntityInterface $entity) {
+    $row = parent::buildRow($entity);
+    $operations = $row['operations'];
+    unset($row['operations']);
+
+    // Override default values to markup elements.
+    $row['#attributes']['class'][] = 'draggable';
+    unset($row['id']);
+
+    $row['label'] = array(
+      '#markup' => check_plain($row['label']),
+    );
+    $dimensions = $entity->get('dimensions');
+    $row['dimensions'] = array(
+      '#markup' => check_plain($dimensions['width'] . 'x' . $dimensions['height'] . ' (' . $dimensions['dppx'] . ' dppx)'),
+    );
+    $row['orientation'] = array(
+      '#markup' => $entity->get('orientation') == 'landscape' ? t('Landscape') : t('Portrait'),
+    );
+    $row['status'] = array(
+      '#markup' => $entity->get('status') ? t('yes') : t('no'),
+    );
+    $row['#weight'] = $entity->get('weight');
+    // Add weight column.
+    $row['weight'] = array(
+      '#type' => 'weight',
+      '#title' => t('Weight for @title', array('@title' => $entity->label())),
+      '#title_display' => 'invisible',
+      '#default_value' => $entity->get('weight'),
+      '#attributes' => array('class' => array('weight')),
+    );
+    $row['operations'] = $operations;
+    return $row;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function render() {
+    return drupal_get_form($this);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, array &$form_state) {
+    $form['entities'] = array(
+      '#type' => 'table',
+      '#header' => $this->buildHeader(),
+      '#empty' => t('There is no @label yet.', array('@label' => $this->entityInfo['label'])),
+      '#tabledrag' => array(
+        array('order', 'sibling', 'weight'),
+      ),
+    );
+
+    foreach ($this->load() as $entity) {
+      $form['entities'][$entity->id()] = $this->buildRow($entity);
+    }
+
+    $form['actions']['#type'] = 'actions';
+    $form['actions']['submit'] = array(
+      '#type' => 'submit',
+      '#value' => t('Save order'),
+      '#button_type' => 'primary',
+    );
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function validateForm(array &$form, array &$form_state) {
+    // No validation.
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, array &$form_state) {
+    $values = $form_state['values']['entities'];
+
+    $entities = entity_load_multiple($this->entityType, array_keys($values));
+    foreach ($values as $id => $value) {
+      if (isset($entities[$id]) && $value['weight'] != $entities[$id]->get('weight')) {
+        // Update changed weight.
+        $entities[$id]->set('weight', $value['weight']);
+        $entities[$id]->save();
+      }
+    }
+
+    drupal_set_message(t('The device settings have been updated.'));
+  }
+}
diff --git a/core/modules/responsive_preview/lib/Drupal/responsive_preview/Form/DeviceDelete.php b/core/modules/responsive_preview/lib/Drupal/responsive_preview/Form/DeviceDelete.php
new file mode 100644
index 0000000..0413b09
--- /dev/null
+++ b/core/modules/responsive_preview/lib/Drupal/responsive_preview/Form/DeviceDelete.php
@@ -0,0 +1,73 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\responsive_preview\Form\DeviceDelete.
+ */
+
+namespace Drupal\responsive_preview\Form;
+
+use Drupal\Core\Form\ConfirmFormBase;
+use Drupal\responsive_preview\DeviceInterface;
+
+/**
+ * Provides a deletion confirmation form for a device entity.
+ */
+class DeviceDelete extends ConfirmFormBase {
+
+  /**
+   * The device being deleted.
+   *
+   * @var \Drupal\responsive_preview\DeviceInterface
+   */
+  protected $device;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormID() {
+    return 'responsive_preview_admin_device_delete_confirm';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getQuestion() {
+    return t('Are you sure you want to delete the device %name?', array('%name' => $this->device->label()));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getCancelPath() {
+    return 'admin/config/content/responsive_preview';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function getConfirmText() {
+    return t('Delete');
+  }
+
+  /**
+   * {@inheritdoc}
+   * @param \Drupal\responsive_preview\DeviceInterface $device
+   *   The device being deleted.
+   */
+  public function buildForm(array $form, array &$form_state, DeviceInterface $device = NULL) {
+    $this->device = $device;
+    return parent::buildForm($form, $form_state);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, array &$form_state) {
+    $this->device->delete();
+    watchdog('responsive_preview', 'Device %name has been deleted.', array('%name' => $this->device->label()));
+    drupal_set_message(t('Device %name has been deleted.', array('%name' => $this->device->label())));
+    $form_state['redirect'] = 'admin/config/content/responsive_preview';
+  }
+
+}
diff --git a/core/modules/responsive_preview/config/responsive_preview.device.desktop.yml b/core/modules/responsive_preview/config/responsive_preview.device.desktop.yml
new file mode 100644
index 0000000..14e5ba9
--- /dev/null
+++ b/core/modules/responsive_preview/config/responsive_preview.device.desktop.yml
@@ -0,0 +1,10 @@
+id: desktop
+label: Typical desktop
+dimensions:
+  width: 1366
+  height: 768
+  dppx: 1
+orientation: landscape
+weight: 5
+status: 1
+langcode: en
diff --git a/core/modules/responsive_preview/config/responsive_preview.device.ipad.yml b/core/modules/responsive_preview/config/responsive_preview.device.ipad.yml
new file mode 100644
index 0000000..c14ecac
--- /dev/null
+++ b/core/modules/responsive_preview/config/responsive_preview.device.ipad.yml
@@ -0,0 +1,10 @@
+id: ipad
+label: iPad
+dimensions:
+  width: 1536
+  height: 2048
+  dppx: 2
+orientation: portrait
+weight: 2
+status: 1
+langcode: en
diff --git a/core/modules/responsive_preview/config/responsive_preview.device.iphone4.yml b/core/modules/responsive_preview/config/responsive_preview.device.iphone4.yml
new file mode 100644
index 0000000..c57d380
--- /dev/null
+++ b/core/modules/responsive_preview/config/responsive_preview.device.iphone4.yml
@@ -0,0 +1,10 @@
+id: iphone4
+label: iPhone 4
+dimensions:
+  width: 640
+  height: 960
+  dppx: 2
+orientation: portrait
+weight: 1
+status: 1
+langcode: en
diff --git a/core/modules/responsive_preview/config/responsive_preview.device.iphone5.yml b/core/modules/responsive_preview/config/responsive_preview.device.iphone5.yml
new file mode 100644
index 0000000..d076c8d
--- /dev/null
+++ b/core/modules/responsive_preview/config/responsive_preview.device.iphone5.yml
@@ -0,0 +1,10 @@
+id: iphone5
+label: iPhone 5
+dimensions:
+  width: 640
+  height: 1136
+  dppx: 2
+orientation: portrait
+weight: 0
+status: 1
+langcode: en
diff --git a/core/modules/responsive_preview/config/responsive_preview.device.nexus4.yml b/core/modules/responsive_preview/config/responsive_preview.device.nexus4.yml
new file mode 100644
index 0000000..d43ffea
--- /dev/null
+++ b/core/modules/responsive_preview/config/responsive_preview.device.nexus4.yml
@@ -0,0 +1,10 @@
+id: nexus4
+label: Nexus 4
+dimensions:
+  width: 768
+  height: 1280
+  dppx: 2
+orientation: portrait
+weight: 3
+status: 1
+langcode: en
diff --git a/core/modules/responsive_preview/config/responsive_preview.device.nexus7.yml b/core/modules/responsive_preview/config/responsive_preview.device.nexus7.yml
new file mode 100644
index 0000000..bf17615
--- /dev/null
+++ b/core/modules/responsive_preview/config/responsive_preview.device.nexus7.yml
@@ -0,0 +1,10 @@
+id: nexus7
+label: Nexus 7
+dimensions:
+  width: 800
+  height: 1280
+  dppx: 1.325
+orientation: portrait
+weight: 4
+status: 1
+langcode: en
diff --git a/core/modules/responsive_preview/config/responsive_preview.devices.yml b/core/modules/responsive_preview/config/responsive_preview.devices.yml
deleted file mode 100644
index 8f4e088..0000000
--- a/core/modules/responsive_preview/config/responsive_preview.devices.yml
+++ /dev/null
@@ -1,50 +0,0 @@
-# References:
-# - http://en.wikipedia.org/wiki/List_of_displays_by_pixel_density
-# - http://www.w3.org/blog/CSS/2012/06/14/unprefix-webkit-device-pixel-ratio/
-# - http://pieroxy.net/blog/2012/10/18/media_features_of_the_most_common_devices.html
-#
-# The device listing and specifications will be updated periodically through
-# minor releases of Drupal.
-
-iphone:
-  label: iPhone 5
-  dimensions:
-    width: 640
-    height: 1136
-    dppx: 2
-  orientation: portrait
-iphone4:
-  label: iPhone 4
-  dimensions:
-    width: 640
-    height: 960
-    dppx: 2
-  orientation: portrait
-ipad:
-  label: iPad
-  dimensions:
-    width: 1536
-    height: 2048
-    dppx: 2
-  orientation: portrait
-nexus4:
-  label: Nexus 4
-  dimensions:
-    width: 768
-    height: 1280
-    dppx: 2
-  orientation: portrait
-nexus7:
-  label: Nexus 7
-  dimensions:
-    width: 800
-    height: 1280
-    dppx: 1.325
-  orientation: portrait
-desktop:
-  label: Typical desktop
-  dimensions:
-    width: 1366
-    height: 768
-    dppx: 1
-  orientation: landscape
diff --git a/core/modules/responsive_preview/lib/Drupal/responsive_preview/Form/DeviceSettingsAddForm.php b/core/modules/responsive_preview/lib/Drupal/responsive_preview/Form/DeviceSettingsAddForm.php
deleted file mode 100644
index 8238873..0000000
--- a/core/modules/responsive_preview/lib/Drupal/responsive_preview/Form/DeviceSettingsAddForm.php
+++ /dev/null
@@ -1,116 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\responsive_preview\Form\DeviceSettingsAddForm.
- */
-
-namespace Drupal\responsive_preview\Form;
-
-use Drupal\Core\Config\ConfigFactory;
-use Drupal\Core\Config\Context\ContextInterface;
-use Drupal\system\SystemConfigFormBase;
-use Symfony\Component\DependencyInjection\ContainerInterface;
-
-/**
- * List tests arranged in groups that can be selected and run.
- */
-class DeviceSettingsAddForm extends SystemConfigFormBase {
-
-  /**
-   * Constructs a DeviceSettingsForm object.
-   *
-   * @param \Drupal\Core\Config\ConfigFactory $config_factory
-   *   The factory for configuration objects.
-   * @param \Drupal\Core\Config\Context\ContextInterface $context
-   *   The configuration context used for this configuration object.
-   * @param \Drupal\Core\Path\AliasManagerInterface $alias_manager
-   *   The path alias manager.
-   */
-  public function __construct(ConfigFactory $config_factory, ContextInterface $context) {
-    parent::__construct($config_factory, $context);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function create(ContainerInterface $container) {
-    return new static(
-      $container->get('config.factory'),
-      $container->get('config.context.free')
-    );
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getFormID() {
-    return 'responsive_preview_device_settings_add';
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function buildForm(array $form, array &$form_state) {
-
-    $form = array(
-      'label' => array(
-        '#type' => 'textfield',
-        '#title' => t('Device name'),
-        '#required' => TRUE,
-      ),
-      'width' => array(
-        '#type' => 'textfield',
-        '#title' => t('Device width'),
-        '#size' => 6,
-        '#required' => TRUE,
-      ),
-      'height' => array(
-        '#type' => 'textfield',
-        '#title' => t('Device height'),
-        '#size' => 6,
-        '#required' => TRUE,
-      ),
-      'dppx' => array(
-        '#type' => 'textfield',
-        '#title' => t('Device dppx'),
-        '#default_value' => 1,
-        '#size' => 4,
-        '#required' => TRUE,
-      ),
-      'orientation' => array(
-        '#type' => 'select',
-        '#title' => t('Default device orientation'),
-        '#default_value' => 'portrait',
-        '#options' => drupal_map_assoc(array('portrait', 'landscape')),
-      ),
-    );
-
-    return parent::buildForm($form, $form_state);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function validateForm(array &$form, array &$form_state) {
-    parent::validateForm($form, $form_state);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function submitForm(array &$form, array &$form_state) {
-    $this->configFactory->get('responsive_preview.devices')->set($form_state['values']['label'], array(
-      'label' => $form_state['values']['label'],
-      'dimensions' => array(
-        'width' => $form_state['values']['width'],
-        'height' => $form_state['values']['height'],
-        'dppx' => $form_state['values']['dppx'],
-      ),
-      'orientation' => $form_state['values']['orientation'],
-    ))->save();
-
-    parent::submitForm($form, $form_state);
-  }
-
-}
diff --git a/core/modules/responsive_preview/lib/Drupal/responsive_preview/Form/DeviceSettingsForm.php b/core/modules/responsive_preview/lib/Drupal/responsive_preview/Form/DeviceSettingsForm.php
deleted file mode 100644
index cbd773e..0000000
--- a/core/modules/responsive_preview/lib/Drupal/responsive_preview/Form/DeviceSettingsForm.php
+++ /dev/null
@@ -1,151 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\responsive_preview\Form\DeviceSettingsForm.
- */
-
-namespace Drupal\responsive_preview\Form;
-
-use Drupal\Core\Config\ConfigFactory;
-use Drupal\Core\Config\Context\ContextInterface;
-use Drupal\system\SystemConfigFormBase;
-use Symfony\Component\DependencyInjection\ContainerInterface;
-
-/**
- * Configure site information settings for this site.
- */
-class DeviceSettingsForm extends SystemConfigFormBase {
-
-  /**
-   * Constructs a DeviceSettingsForm object.
-   *
-   * @param \Drupal\Core\Config\ConfigFactory $config_factory
-   *   The factory for configuration objects.
-   * @param \Drupal\Core\Config\Context\ContextInterface $context
-   *   The configuration context used for this configuration object.
-   */
-  public function __construct(ConfigFactory $config_factory, ContextInterface $context) {
-    parent::__construct($config_factory, $context);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function create(ContainerInterface $container) {
-    return new static(
-      $container->get('config.factory'),
-      $container->get('config.context.free')
-    );
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getFormID() {
-    return 'responsive_preview_device_settings';
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function buildForm(array $form, array &$form_state) {
-    $devices = $this->configFactory->get('responsive_preview.devices')->get();
-
-    $form['devices_listing'] = array(
-      '#type' => 'table',
-      '#title' => t('Device descriptions available for preview.'),
-      '#header' => array(
-        'label' => array(
-          'data' => t('Label'),
-        ),
-        'width' => array(
-          'data' => t('Width'),
-        ),
-        'height' => array(
-          'data' => t('Height'),
-        ),
-        'dppx' => array(
-          'data' => t('DPPX'),
-          'class' => array(RESPONSIVE_PRIORITY_MEDIUM),
-        ),
-        'orientation' => array(
-          'data' => t('Orientation'),
-          'class' => array(RESPONSIVE_PRIORITY_MEDIUM),
-        ),
-      ),
-    );
-
-    foreach ($devices as $device => $config) {
-      $form['devices_listing'][$device] = array(
-        'label' => array(
-          '#type' => 'textfield',
-          '#title' => t('Device name'),
-          '#size' => null,
-          '#default_value' => $config['label'],
-          '#required' => TRUE,
-        ),
-        'width' => array(
-          '#type' => 'textfield',
-          '#title' => t('Device width'),
-          '#default_value' => $config['dimensions']['width'],
-          '#size' => 6,
-          '#required' => TRUE,
-        ),
-        'height' => array(
-          '#type' => 'textfield',
-          '#title' => t('Device height'),
-          '#default_value' => $config['dimensions']['height'],
-          '#size' => 6,
-          '#required' => TRUE,
-        ),
-        'dppx' => array(
-          '#type' => 'textfield',
-          '#title' => t('Device dppx'),
-          '#default_value' => $config['dimensions']['dppx'],
-          '#size' => 4,
-          '#required' => TRUE,
-        ),
-        'orientation' => array(
-          '#type' => 'select',
-          '#title' => t('Default device orientation'),
-          '#default_value' => $config['orientation'],
-          '#options' => drupal_map_assoc(array('portrait', 'landscape')),
-        ),
-      );
-    }
-
-    return parent::buildForm($form, $form_state);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function validateForm(array &$form, array &$form_state) {
-    parent::validateForm($form, $form_state);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function submitForm(array &$form, array &$form_state) {
-    $config = $this->configFactory->get('responsive_preview.devices');
-
-    foreach ($form_state['values']['devices_listing'] as $device => $settings) {
-      $config->set($device, array(
-        'label' => $settings['label'],
-        'dimensions' => array(
-          'width' => $settings['width'],
-          'height' => $settings['height'],
-          'dppx' => $settings['dppx'],
-        ),
-        'orientation' => $settings['orientation'],
-      ));
-    }
-
-    $config->save();
-
-    parent::submitForm($form, $form_state);
-  }
-
-}
diff --git a/core/modules/responsive_preview/responsive_preview.module b/core/modules/responsive_preview/responsive_preview.module
index 05aaf51..4ac5daa 100644
--- a/core/modules/responsive_preview/responsive_preview.module
+++ b/core/modules/responsive_preview/responsive_preview.module
@@ -18,6 +18,9 @@ function responsive_preview_help($path, $arg) {
       $output .= '<p>' . t('To launch a preview, first click the toolbar tab with the small device icon. The tab has the title "@title". A list of devices will appear. Selecting a device name will launch a preview of the current page within the dimensions of that device.', array('@title' => t('Preview page layout'))) . '</p>';
       $output .= '<p>' . t('To close the preview, click the close button signified visually by an x.') . '</p>';
       return $output;
+    case 'admin/config/content/responsive_preview':
+      $output = '<p>' . t('Configure the set and order of available devices on this page for responsive site preview. The list of devices is shown in a dropdown accessible from the toolbar tab with a small device icon.') . '</p>';
+      return $output;
   }
 }

@@ -26,15 +29,29 @@ function responsive_preview_help($path, $arg) {
  */
 function responsive_preview_menu() {
   $items['admin/config/content/responsive_preview'] = array(
-    'title' => 'Responsive Preview',
+    'title' => 'Responsive preview',
     'description' => 'Configure device listings for content preview.',
-    'route_name' => 'responsive_preview_device_settings',
+    'route_name' => 'responsive_preview_device_list',
   );
   $items['admin/config/content/responsive_preview/add'] = array(
     'title' => 'Add preview device',
-    'description' => 'Add a device by defining its specifications.',
+    'route_name' => 'responsive_preview_device_add',
     'type' => MENU_LOCAL_ACTION,
-    'route_name' => 'responsive_preview_device_settings_add',
+    'weight' => 1,
+  );
+  $items['admin/config/content/responsive_preview/manage/%responsive_preview_device'] = array(
+    'title' => 'Edit device',
+    'route_name' => 'responsive_preview_device_edit',
+  );
+  $items['admin/config/content/responsive_preview/manage/%responsive_preview_device/edit'] = array(
+    'title' => 'Edit',
+    'type' => MENU_DEFAULT_LOCAL_TASK,
+  );
+  $items['admin/config/content/responsive_preview/manage/%responsive_preview_device/delete'] = array(
+    'title' => 'Delete',
+    'route_name' => 'responsive_preview_device_delete',
+    'type' => MENU_LOCAL_TASK,
+    'weight' => 10,
   );
   return $items;
 }
@@ -42,20 +59,22 @@ function responsive_preview_menu() {
  * Returns a list of devices and their properties from configuration.
  */
 function responsive_preview_get_devices_list() {
-  $devices = config('responsive_preview.devices')->get();
+  $devices = entity_load_multiple('responsive_preview_device');
+  uasort($devices, array('Drupal\responsive_preview\Plugin\Core\Entity\Device', 'sort'));

   $links = array();
-  foreach($devices as $name => $info) {
-    $links[$name] = array(
+  foreach ($devices as $device) {
+    $dimensions = $device->get('dimensions');
+    $links[$device->id()] = array(
       '#type' => 'html_tag',
       '#tag' => 'button',
-      '#value' => $info['label'],
+      '#value' => $device->label(),
       '#attributes' => array(
         'class' => array('device', 'icon', 'icon-active'),
-        'data-responsive-preview-name' => $name,
-        'data-responsive-preview-width' => (!empty($info['dimensions']['width'])) ? $info['dimensions']['width'] : '',
-        'data-responsive-preview-height' => (!empty($info['dimensions']['height'])) ? $info['dimensions']['height'] : '',
-        'data-responsive-preview-dppx' => (!empty($info['dimensions']['dppx'])) ? $info['dimensions']['dppx'] : '1',
+        'data-responsive-preview-name' => $device->id(),
+        'data-responsive-preview-width' => (!empty($dimensions['width'])) ? $dimensions['width'] : '',
+        'data-responsive-preview-height' => (!empty($dimensions['height'])) ? $dimensions['height'] : '',
+        'data-responsive-preview-dppx' => (!empty($dimensions['dppx'])) ? $dimensions['dppx'] : '1',
       ),
     );
   }
@@ -64,6 +83,20 @@ function responsive_preview_get_devices_list() {
 }

 /**
+ * Fetches a responsive preview device by ID.
+ *
+ * @param string $id
+ *   A string representing the device ID (machine name).
+ *
+ * @return
+ *   A fully-loaded device object if a device with the given ID exists,
+ *   or FALSE otherwise.
+ */
+function responsive_preview_device_load($id) {
+  return entity_load('responsive_preview_device', $id);
+}
+
+/**
  * Prevents the preview tab from rendering on administration pages.
  */
 function responsive_preview_access() {
diff --git a/core/modules/responsive_preview/responsive_preview.routing.yml b/core/modules/responsive_preview/responsive_preview.routing.yml
index 07badd2..698c8c6 100644
--- a/core/modules/responsive_preview/responsive_preview.routing.yml
+++ b/core/modules/responsive_preview/responsive_preview.routing.yml
@@ -1,12 +1,28 @@
-responsive_preview_device_settings:
+responsive_preview_device_list:
   pattern: '/admin/config/content/responsive_preview'
   defaults:
-    _form: 'Drupal\responsive_preview\Form\DeviceSettingsForm'
+    _content: '\Drupal\Core\Entity\Controller\EntityListController::listing'
+    entity_type: 'responsive_preview_device'
   requirements:
     _permission: 'administer site configuration'
-responsive_preview_device_settings_add:
+
+responsive_preview_device_add:
   pattern: '/admin/config/content/responsive_preview/add'
   defaults:
-    _form: '\Drupal\responsive_preview\Form\DeviceSettingsAddForm'
+    _entity_form: responsive_preview_device.default
+  requirements:
+    _permission: 'administer site configuration'
+
+responsive_preview_device_edit:
+  pattern: '/admin/config/content/responsive_preview/manage/{responsive_preview_device}'
+  defaults:
+    _entity_form: responsive_preview_device.default
+  requirements:
+    _permission: 'administer site configuration'
+
+responsive_preview_device_delete:
+  pattern: '/admin/config/content/responsive_preview/manage/{responsive_preview_device}/delete'
+  defaults:
+    _form: '\Drupal\responsive_preview\Form\DeviceDelete'
   requirements:
     _permission: 'administer site configuration'