Window non tilt channel balance

With this combination of attachments, you could have either a S380 or S385 channel balance. You need to measure your bottom attachment as shown below. The Series 380 has a 1" bottom attachment, and the Series 385 has a 1-3/32" attachment. It looks like you'll need a 3030 spring weight option based on your stamp but there is also a chart on the product page that explains how to choose your option based on your windows sash weight.

Thank you and let us know if you have any other questions or concerns.

Comparison of 15-004 and 15-005