26 4 GP CALDWELL

Thanks for posting. This looks like either the S380-27 or S385-27. The only difference between these two channel balances is the 'depth' of the bottom nylon shoe, or the 'heel-to-toe' measurement. See the diagram below for reference. Compare both with your old hardware to see what matches best. For a stamp option choose 2640.

Comparison of the S378, S380 and S385 balance shoes.