Bob from SWISCO responded:
November 5, 2021
This is actually typical of non-tilt window channel balances: the first two digits of the stamp are usually one less than the length of the metal channel--those two digits refer to the height of visible glass in the window, which is usually 1" less than the metal channel length. So you have either an S351-28 or S390-28. The only difference between these two balances is the depth of the bottom nylon shoe, or the 'heel-to-toe' measurement, so compare both with your old hardware to see what matches best. For a stamp option you will choose 2730. Comparison of the S351 and S390 balance shoes.
|