channel balance (need left and right)

Thanks for posting. This looks like either an S351-29 or S390-29 Channel Balance. The only difference between these two balances is the depth of the bottom nylon shoe, or the 'heel-to-toe' measurement, so compare both with your old hardware to see what matches best. See the illustration below for reference. In either case, for a stamp option go with 2830.

Comparison of the S351 and S390 balance shoes.