Bob from SWISCO responded:
October 5, 2020
I agree, this looks like either an S351-36 or S390-36, depending on the depth of the bottom nylon shoe. That stamp code of 3590 is from a rating system no longer in use. To know what stamp option you need, obtain the exact weight of the window sash. You can then match that exact weight with one of the weight ranges listed alongside each stamp option on the product page. |