Balance spring identification

Question

I'm trying to verify a replacement part for my non tilt window balance spring. It measures 30 inches long. I believe it's a half inch. Photos included.

Jasmine · Accepted Answer

Thanks for reaching out to us! Your balances are either the S380-30 with a 1" shoe or the S385-30 with a 1-3/32" shoe. You'll need to select the 2960 stamp option.

To determine which series is needed for your window, look over the dimensions from the diagram below to confirm the depth of your bottom shoe. Keep in mind, there is a chance that it could measure 7/8". If so, please let me know as these will need to be a custom assembly.

The metal clip securing the balance in the channel in the 16-002 Take-Out Clip.

Comparison of the S378, S380 and S385 balance shoes.