I think this is a spacer. There is one on each side of the top of the front window on an aluminum double hung window. I took the one in the photos out in order to be able to remove the window so I can replace the chanel balances. I need 6 of them. They are about 1 3/4" tall.
Tom from SWISCO responded:
May 24, 2023
This top sash guide is very similar in design to our 18-110. This may be just the part you need, but I recommend that you review our specs just to verify.