Window Part, retainer
A contractor from Florida says:
January 26, 2015
Hey folks, I got balances that fit for this window and then realized the these pieces were missing as well. They retain the top of the balance in the side of the window. Apparently time and sunlight has gotten the best of them.
Paul from SWISCO responded:
January 27, 2015
Hello! Looks like you have Pan Am windows, which would mean you should consider our 18-187 top sash guide. It looks very similar to your picture, but look it over just in case.