Window balance

Hello, thank you for posting,

With this combination of attachments, you could have either an S380 or S385 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 will need a 27" balance and the original 26D stamp should translate to a 2640 option that can support a  19 to 26 lb. We recommend weighing the window sash to confirm! Yes, if the balance spring is too strong, the window will be too hard to close or not close properly. 

Let us know if you have any additional questions! 

Comparison of the S378, S380 and S385 balance shoes.