Need help identifying window balance spring

Thank you very much for your patience during this busy season.

Take a look at the S380-22 and S385-22 channel balances. The important difference is the depth of the bottom shoe, so you will have to measure as shown below. You can also select the 2140 stamp option for the new balances. 

Please let us know if you have any questions. 

Comparison of the S378, S380 and S385 balance shoes.