Channel balance for a BFS window

It looks like you have a Series 395 to me. The shoe likely just wore down from age; if it's depth is at all greater than 1", then it was probably originally 1-1/8".

Now, please confirm the length of the metal channel. Be sure not to include the nylon fittings on both ends in that measurement. If it's indeed 28", then that's a very unusual stamp code for this balance. I advise getting the exact weight of the window sash. Let me know what the metal channel length and sash weight is, and we'll go from there.

Hi Greg. Yes, the sash is the movable part of the window with glass. That said, if the stamp code reads 27-4, you should be fine going with a stamp option of 2740, which designates a balance meant to support a window sash in the weight range of 19 through 26 pounds.