On the part itself is stamped B.S.I. 24xHD
I have 6 windows where all lower sash mechanisms are broken. Do you have that replacement part and can it be replaced without major surgery? Thanks
Spring mechanism
Quick Learner from Winchendon, MA
Sep 15, 2026 9:59 am
2 Replies
Tom from SWISCO
Sep 21, 2026 10:02 am
I'm not sure what you have, unfortunately. There are dozens of different balances with that stamp. It's not a product code or anything, it just indicates the strength of the spring.
Our service requires clear and unobstructed photos of the hardware in question at minimum. In order to figure out what Series this is, I need you to remove an undamaged version of this balance from the window and show me clear pictures of it in undamaged condition. I specifically need to see the top end, bottom end, stamp, and whatever clip or shoe is at the end of the cord.
Once you provide those photos I can check our stock for a replacement.