Caldwell 25 2 IS window balance channel

Thank you for posting your photos to our discussion board. Have a look at both our S351-26 and S390-26 channel balances. Both of these balances appear to be identical, but, the difference between the two lie within the 'depth' measurement of the bottom balance shoe. You will need to measure the 'depth' of your bottom balance shoe, the way shown in the diagram below, to determine which of the two balances is the better match. Whichever one chosen will use a 2520 option that supports a sash weight of 9-15 pounds. 

Comparison of 15-001 & 15-002