3240 (marking on my channel balance)

Hello there. It looks like you have either an S380-33 or S385-33 Channel Balance. The only difference between these two balances is the 'depth' of the bottom nylon shoe, or the 'heel-to-toe' measurement. See the diagram below for reference. Compare both balances with your old hardware to see what matches best. For a stamp option go with 3240.

Comparison of the S378, S380 and S385 balance shoes.