Replacement spiral balances for a house built in 1938

A home owner from Milwaukee, WI says:

I just moved into a house and there is some damage to several of the spiral balances. I'd like to replace these as I'm planning to spend the next few weeks repairing storm windows and getting several of the windows unstuck. I'm not sure of which replacement parts that I need. The house was built in 1938 and the windows are the non-tilt design.

Measurement of the tube diameter points to the 3/8" version.

After getting that far, I'm not positive about which model to order. The attached .pdf file contains pictures. My guess is that I need the Series 305 in the 30" size (a pair of them). I'll likely need about 5 pairs--I'm in the process of confirming that the other windows are the same dimension.

Thank you for your help.

User submitted photo of window and spiral balance.
Profile picture of Paul
Paul from SWISCO responded:
You will need our series 500 window balances. It looks like you will need the 28" S500-28 for top and the 30" S500-30 for the bottom sash. You will need the sash bracket #17-007 for each balance and a charging tool #75-005. To be safe, recheck the balance sizes from a somewhat good balance on another window of the same size to confirm that you do indeed need a 28" and 30" balance.
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