Block and tackle window balance set needing replacement

Question

Please suggest a replacement for this balance set. The channel is 27" long, 5/8" wide, ~9/16" deep. Image 5517 when fully opened shows the entire length, both sides. MARKING is 26 3 AX CMC 11.  I have more photos available, only five could be uploaded.Thank you!

Bob · Accepted Answer

Hey there. This looks like either the S378-27, S380-27, or S385-27 Channel Balance. The only difference between these 3 balances is the depth of the bottom nylon shoe, or the 'heel-to-toe' measurement. See below. Measure your old balance's shoe to see what matches best. For a stamp option choose 2630.

Comparison of the S378, S380 and S385 balance shoes.