Channel block & tackle window balance spring. Two per window. The channel measurement is 29 however the oart ia stamped 28D.
thanks for your help
Channel block & tackle window balance spring

Quick Learner from Florida
Dec 23, 2024 1:59 pm
5 user uploaded images
2 Replies

Lauren from SWISCO
Dec 26, 2024 3:44 pm


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 29" balance and the original 28D stamp should translate to a 2840 stamp option that can support a 23 to 28 pound window sash. We recommend weighing the sash to confirm before purchasing. Let us know if you have any additional questions!

Comparison of the S378, S380 and S385 balance shoes.
Related Products
Related Videos
Related Guides