A home owner from louisville Kentucky says:
May 3, 2016
I Have 2 large vinyl dbl hung windows that have spiral ballances looks like your seris 600 x 33" balance is the one I need Sash weighs 40 pounds what color do I need or do I have to have them made Evan when new were heavy to lift
Tom from SWISCO responded:
May 4, 2016
If your sash weighs 40 pounds, then the Black Tip option for the S600-33 may work for you. This can carry a sash weight of 31 through 40 pounds.