A-S 7873 (AT9) Wheel Replacement for Sliding Glass Door

Thanks for writing in. The part in your photo I believe is actually only the inside portion of a complete roller assembly. There should be an outer housing, perhaps still installed in the door. You need to extract that outer housing to be entirely certain what you're working with. Now, based on that stamp, I believe this roller assembly was made by Allen Stevens, who went out of business, and the roller you might want is our 81-278. Compare the dimensions below to your entire assembly to see if this matches what you need. Let me know if you have further questions, including if there's any issues getting the outer housing out.

Alternate image for 81-278