balance and sash guide replacement

Question

good day.
snapped the spring string part of one side of my non-tilt window. Im lost on the replacement need. not so much the measurement part... 26 4, but with the rest, LW CMC 11. Ive seen IW, GW, AX... but have no idea what that means. Cant seem to find any LW CMC 11. I've confirmed the balance is 5/8 deep by 27 long, metal to metal. end tabs have wings.
also, i broke the inner channel top sash guide also. it seems your 18-188 is the near identical match? 1.5 long. 5/8 wide 9/16 deep is my measurements. flat top edges.

any assistance, and education is appreciated. especially for the LW CMC 11 part.

Casey · Accepted Answer

Hello,

With this combination of attachments, you could have either the S380-27 or S385-27 channel balance. You’ll need to measure as shown below. The Series 380 has a 1" bottom attachment, and the Series 385 has a 1-3/32" attachment. You'll also need 2640 spring strength options for your replacement balances.

Comparison of the S378, S380 and S385 balance shoes.

If you'd like us to confirm if the 18-188 would be our best match for your top sash guide, we would need to see photos of an undamaged part removed from one of your windows. Thank you!

Alternate view of 18-188