Window balance for non tilt window 1/2 inch wide 27 inch long

Question

Dear Sir,
The string of the balance broke. It is inside a non-tilt milgard up and down window. Would appreciate very much if you can tell me the name of the replacement part.
Thanks,
Mark

Window balance for non tilt window 1/2 inch wide 27 inch long

Tom · Accepted Answer

Welcome to SWISCO. It seems you need an S385-27 or an S380-27 with a "2640" stamp option, but I can't tell which of the two you need. The only difference between them is the width of the bottom shoe. To determine your balance Series, measure the shoe as depicted in the image below. If the shoe measures 1-3/32" as shown, you need the S385-27. For a 1" shoe, you need to choose an S380-27. Either way, the stamp option should be "2640". Measure your shoe carefully before you make a decision:

Comparison of the S378, S380 and S385 balance shoes.