Window balance

Thanks for posting. Alcoa windows use a number of different balances, so I am afraid I can't cross-reference what you need from this information alone. You'll need to show us the balances in the window for us to narrow down what you need. This article here tells you everything you need to know about all the different balances we carry. 

Thanks! This appears to be a typical tilt window spiral balance. That means you only have two options: either the 3/8" diameter Series 900 or the 9/16" diameter Series 600. The diameter, in this case, references the outer plastic tube. 

Your next step should be to measure the tube to verify which option is what you need. You very likely have the larger Series 600 but it can't hurt to check.