Window balance replacement part reqeust

Question

The string broke in my window. The writing on the balance says Caldwell 17 3 RT.

Bob · Accepted Answer

This looks like either an S380-18 or S385-18 Channel Balance. The only difference between each of these channel balances is the depth of the bottom nylon shoe, or the 'heel-to-toe' measurement. The image below depicts the difference. Compare both with your old hardware to see what matches best. For a new stamp option choose 1730.

Comparison of the S378, S380 and S385 balance shoes.