A quick learner from sliding patio window door says:
January 30, 2013
I need a roller assembly and a track cap for a Sliding Window patio door. I have a picture of the parts, but cant find them in your catalog.
Roller Assembly 3 in length X 1 1/2 in tall X 1/2 in wide
metal wheel 1 in
70 in track cap
Tom from SWISCO responded:
January 31, 2013
Thanks for posting! Please see SWISCO product code 81-242, Roller Assembly. This appears very similar to what you have. Compare the measurements and let us know if they differ in any way.