Looking to get help identifying these parts

Hi there!

For this balance, you could have either an S380-21 or S385-21 channel balance. You’ll need to measure as shown below. The Series 380 has a 1" bottom attachment, and the Series 385 has a 1-3/32" attachment. You'll also need a spring strength option of 2030. 

If you have any further questions just let us know. 

Comparison of the S380 and S385 balance shoes.

It's possible that your bottom shoe has worn down over the years. To be sure you're getting the correct balance for the other set, can you show us clear pictures of the top and bottom attachments? We'd also like to know the stamp on the metal channel. 

The depth of the shoe in each case appears to exceed 1", so I think our Series 385 would be a safe bet. However it is ultimately up to you. It is a subtle difference and it's not always easy to tell from just a photo of a ruler, so you shouldn't take my word for it. Ultimately the choice is yours.