Extended-Travel Channel Balance Quote

I agree, our S377-31 looks like a great match for your old balance. If your window does use the 18-042 top sash guide then the S377-31 would be my top recommendation; I've never known this window to use anything else.

Odds are your shoe is smaller because it wore down over time from friction. In a worst case scenario, if the shoe on our S377-31 ends up being too big, you can always shave it down a little to make up the difference. I've done that myself in a pinch and it works just fine. However I don't think that will even be necessary.