Window Sash replacement

Thanks for posting. I agree, this is either an S380-23 or S385-23. The shoe depth, or 'heel-to-toe' measurement on the bottom nylon fitting, is the only difference between these two balance Series. See the diagram below for reference, and compare both with your old hardware to confirm what you're working with. I believe your old stamp reads 22B, which conforms to our stamp option of 2220, so that is what you'd select for your replacement balance's stamp. Let me know if you have any other questions.

Comparison of the S378, S380 and S385 balance shoes.