Balance parts 26 4

Hello,

With this combination of attachments, you could have either the S380-27 or S385-27 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 2640 spring strength options for your replacement balances. Thank you and let us know if you have any other questions or concerns.

Comparison of the S380 and S385 balance shoes.

Unfortunately, measurements can not be used to calculate the weight of the window due to the different types of materials and glass thickness that it could have. With that being said, the 26 4 stamp on your balances indicates that you would use 2640 strength options to support a sash between 19-26 pounds.