Window balance 1
A home owner from alameda CA says:
March 14, 2016
1/2 with with spring and string (26 2 EU CMC4)
Tom from SWISCO responded:
March 16, 2016
Thanks for posting. Sounds like you have a 27" block & tackle balance with a stamp option of 2620. I'm afraid that's all I can tell based on your information, though. Now you just need to pick out the top and bottom fittings in order to determine the Series.
I recommend that you look at our Channel Balance Home Page and follow the steps in order to find the Series that best matches what you have.