I see two different kinds on your site and want to understand if there are quality differences.
Thanks,
Charlie

Good morning, Charlie! Thanks for posting. I'm afraid that I cannot really identify this roller while it's still installed in the door. Is there any way you can remove it so that I can see the whole unit?
In the meantime, take a look at our Pella Single Wheel Roller Assemblies for Sliding Glass Patio Doors. Are any of these the two rollers you mentioned? If you let me know which ones you were talking about, I could tell you the differences.