Looking for to identify this plastic part

Question

Plastic part on the side of the window channel casing. Not sure if there are supposed be one on each side.

User submitted a photo of a top sash guide.

Paul · Accepted Answer

Yes, there should be two of these parts on each sash. It's hard to tell exactly what you have based on this picture, though, as yours is very damaged. Is there any way we can see one that isn't broken? In the meantime, take a look at our 18-008 and 18-171 and see if either match yours.