Possible to populate a field based on the selection of another field?

I am wondering if this is the module I am looking for. I'd appreciate any input.

I have two fields: part number & description. The part number is going to be a text field that the user is able to fill in with a company part number. I have the part numbers and descriptions of those part numbers. I would like the description field to populate with the description so the customer can confirm they typed in the correct number.

Thanks!