Unidentified balance pivot shoe

Thanks for posting. You are showing us a T-Lock Shoe. The T-Lock Shoe is an attachment at the end of your window's channel balances that acts as a pivot point for the window sash. It's a bit hard to tell what T-Lock Shoe you need with it still in the window, but see either our 15-195 1-1/4" T-Lock Shoe, or our 15-194 1" T-Lock Shoe. Remove your shoe from the window and compare it to both parts to see which is the best match.