Replacement specifications for Block and Tackle type vinyl window counterbalance

Question

The stamped marking is 32 4 FX CMC 11.  The length of the channel, excluding the plastic inserts on either end, is 33"

Bob · Accepted Answer

Hello there. This looks like either an S351-33 or S390-33 Channel Balance. The only difference between these two balances is the 'depth' of the bottom nylon shoe, or the 'heel-to-toe' measurement. See below. Measure your old balance's shoe depth to see what matches best. For a stamp option choose 3240.

Comparison of the S351 and S390 balance shoes.