29 4 GX CMC 11

Hello there. This looks like either an S380-30 or S385-30. The only difference between these two balances is the depth of the bottom nylon shoe, or the 'heel-to-toe' measurement. See the illustration below for reference. Compare both with your old balance to see what matches best. For a stamp option go with 2940.

Comparison of the S378, S380 and S385 balance shoes.