Opentopomap with openlayers 2.0

I'm not sure if this is the correct way to post this so apologies if not.

I've recently come across the excellent openlayers module. The lack of a topographical map with contours was a bit of an issue for me until I found opentopomap.

Adding a base map was not entirely clear to me, but after some trial and error, here are the settings for others who wish to do the same:

The layer type is XYZ

and the URL is
either:-
http://opentopomap.org/tiles/${z}/${x}/${y}.png

or:-
http://a.tile.opentopomap.org/${z}/${x}/${y}.png
http://b.tile.opentopomap.org/${z}/${x}/${y}.png
http://c.tile.opentopomap.org/${z}/${x}/${y}.png

Apparently the second option is preferred due to server load issues.

I hope this is helpful to someone else!