window balance stamped 28A and 28B

Hello,

With this combination of attachments, you could have either an S380-29 or S385-29 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 2810 spring strength options for your 28A balances and 2820 for the 28B balances. Keep in mind that both balances form each window should have the same stamp code.

If one of the windows has no stamp on the balances, you'll need to weigh your sash to determine which strength option you'll need. There is a chart on the balance product page that explains how to choose your option based on the sash weight. Thank you and let us know if you have any other questions or concerns.

Comparison of the S380 and S385 balance shoes.