29" long, 1/2" wide and the width of the shoe is 1". From what I have seen in your diagrams I'm almost sure that I need a S380-29. The stamp on the channel looks like it says: 28R, but it could be 28B, but the window weighs less than 12 lbs, so I believe I need a 2810.
Please let me know if you agree with what I have found A.S.A.P. so I can order 2 of them.
Thank you, Mike
Hello,
I agree that as long as the bottom fitting measures 1" deep, you would need the S380-29 channel balance. It's tough to make out the stamp code shown in your photos but I suspect that it may actually be 28B, which would correspond to 2820 strength options for your replacement balances. They would be calibrated to support a sash between 9-13 lbs. Thanks for posting.
