Top Sash Guide
A contractor from Litchfield Park, AZ says:
January 18, 2016
I need help identifying this part. I don't see anything on your site. The one picture is what I believe the part is supposed to look like when it is not broken.
Paul from SWISCO responded:
January 21, 2016
I believe our 18-188 could be a good match. It's a little different, but it may still serve the same function. Let me know what you think.