Del Mar Eng. Long Beach Cal. Pat. pending.
A quick learner from Vancouver WA says:
June 29, 2016
Single wheel rollers for a sliding glass door. Seen some pictures of other rollers that look close but I figure I'll let the experts take a look.
Dave from SWISCO responded:
July 1, 2016
This looks a lot like our 81-162. I recommend carefully looking it over to confirm that the dimensions are all the same, including the wheel diameter. If not, let me know how they differe and we will try our best to find a better match.