Caldwell 20-4

Hello there. That 20-4 stamp is actually the identifier for the weight this balance can support. To confirm its identity, I need to also see the nylon fitting on the other end of the balance. The combination of fittings used is what determines the kind of balance you have. We should be able to narrow this all down from there.

That's perfect, thanks. This looks like either an S380-21 or S385-21. The only difference between these two channel balances is the depth of the bottom nylon shoe, or the measurement from 'heel' to 'toe'. See the illustration below for reference. Compare both with your old balance to see what matches best. In either case, for a new stamp option choose 2040.

Comparison of the S380 and S385 balance shoes.