Series # ?

Thanks for posting. Based on the attachments, I think this is either a Series 351 or Series 390 Channel Balance. The difference between these two Series is the depth of the bottom nylon shoe, as shown below. Compare both with your old hardware to see what Series matches best. See the video below for further details about how to identify replacement channel balances. Let us know if you have further questions.

Comparison of the S351 and S390 balance shoes.

You're very welcome, and happy New Year to you, as well!