Channel balance

Question

Hello, I'm looking for the original channel balance for my vertical lift bathroom window.
The channel length is 27"
Channel depth is 5/8"
The part has an ID stamp that shows 2640

Thanks

Bob · Accepted Answer

Thanks for posting. It appears you have either our S351-27 or S390-27. The only difference between these two channel balances is the depth of the bottom nylon shoe. See the diagram below for reference. Measure your old shoe's depth to see what matches best. In either case for a new stamp option go with 2640.

Comparison of the S351 and S390 balance shoes.