I think I have the S385-20

A home owner from Oregon says:
August 8, 2017
I believe the S385-20 is the replacement channel balance that I need, according to the photos & measurements.
But I am confused by the stamped numbers on the item, as in the photo. Our guess is that our window is about 30" wide & weighs 20-25lb. We are not at the house where this window is. Other windows in the house are Viking, this one is not marked.
What do the numbers tell you? Will we need to actually weigh the window to know which item to order?
S385-20
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Tom from SWISCO responded:
August 10, 2017
Thank you for contacting us. I do see that you mentioned that your window sash weighs between 20-25 pounds, but we highly recommend that you weigh your sash to confirm the precise weight of your sash. From there you can correspond that number to the sash weight range chart listed on the respective product page.
20" Series 385 Channel Balance
20" Series 385 Channel Balance
S385-20
$9.38
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