Need help identifying two sash balance replacement parts

A quick learner from charlotte, nc says:
Balance 1:
Markings - 2900 BSI KK
29 inches long

Balance 2
Markings - 3500 BSI JF
35 inches long

also including a photo of the brake for reference

User submitted photos of a window balance.
Profile picture of Paul
Paul from SWISCO responded:
Good afternoon. For the pivot shoe, check out our 15-129 and see how its dimensions compare to your own hardware. As for the balances, I think they look pretty similar to our Series 770 channel balance. What do you think? I'm not so sure what options you'd need, though. I recommend that you weigh your sashes and see what option on the S770-29 and S770-35 weight chart match them, respectively.
A quick learner from nc says:
Looks about right. I weighed the sash for both and placed my order.

Reply to Thread
Use this form to ask a follow-up question or to share your experience regarding this subject.
(your email address will be kept private and is only used to inform you when a response has been made)