Sliding screen door
Thank you for your patience during this busy season. Unfortunately, it's not possible to identify rollers while they're still installed. This service requires clear and unobstructed photos of all parts. Too many key details are obscured.
Once you show me an unobstructed photo, we can check our inventory for a match.
That's a difficult question to answer without knowing what it is to begin with. Depending on what we're dealing with here, it could be anything from something that snaps onto the screen frame corner, to being permanently affixed to it. In the case of the latter example, disassembly of the frame would be a necessary step.
If you aren't familiar with that kind of project, then you may want to consider contacting a local professional to do it for you.