Need help Identifying the parts I need to rebuild 2 big windows 1 small window

Hello,

This looks like our S377 channel balance but I'd recommend you double check your stamps and the length of the metal channel. Normally, the first two numbers of your stamp will be one less than the length of the metal channel. Your balance with a 1220 stamp should be an S377-13. I suspect that there was a typo somewhere for your longer balance. Double-check your stamp and channel measurement to be sure you choose the correct replacement balance. Thank you!