Caldwell channel counterbalance 12-9

Thanks for posting. This might be either our S351-13 or S390-13. The difference between these two balances is the depth of the bottom nylon shoe, or the 'heel-to-toe' measurement. Compare both with your old hardware to see what matches best. See the diagram below for reference.

Comparison of the S351 and S390 balance shoes.

You then have to choose a stamp option, which designates the strength of the balance. Your old balance's stamp of 12-9 is from an outdated rating system. To know what stamp to select, weigh the window sash that these balances support. You can then match that exact weight with one of the weight ranges listed alongside each stamp option under the product description of either the S351-13 or S390-13 product page. 

You're welcome! Please feel free to reach out if we can be of any further assistance.