Window balancer replacements

Thanks for your post. Based on the stamp, I believe the length of the metal channel should be 23". That said, you'll need either the S378-23 or the S380-23 to replace your balances. To confirm the correct series, you'll need to measure the depth of the bottom shoe.

A pair of 2230 stamped balances will support a sash weighing 12 to 19lbs.

Comparison of the S378, S380 and S385 balance shoes.