Bob from SWISCO responded:
June 8, 2020
This looks like either an S351-31 or S390-31. The only difference between these two balances is the 'depth' of the bottom nylon shoe, so compare both with your old hardware to see what matches best. You will need a stamp option of 3050. As far as wings go, you really only want to use winged balances to replace old balances that also had wings. They aren't better or worse than balances with wingless fittings; it simply affects the compatibility with the window track. |