Need help identifying sash balance

A handy person from Florida says:
January 4, 2021
Hi and thanks in advance for your help. I just bought a home in FL, and two windows (same size) need new sash balancers. The windows are heavy/ hurricane grade, about 32" wide by 50" high (each pane), non-tilt.

Metal is 29" long, nearly 5/8" width, and 1/2" depth. The only stamp is 28G so I don't know how to choose sash weight. It appears to be Caldwell 29" Series 380, not 385.

See attached pics...
Matt
Thumbnail of the uploaded file named window sash balance IMG_4122.jpg
Thumbnail of the uploaded file named window sash balance IMG_4123.jpg
Thumbnail of the uploaded file named window sash balance IMG_4124.jpg
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Tom from SWISCO responded:
January 5, 2021

Hello, Matt. As long as the dimensions of your nylon fittings match those of the 19-005 and 15-005, which are what come with the Series 380, then you should be good to go.

As for stamp, 28G typically corresponds to our 2870 option, but you might want to weigh your sash to be 100% sure.
A handy person from Florida says:
January 6, 2021
The nylon fittings seem to be a very close match, though maybe not perfect. But nothing else is close.

I don't have an easy way to weigh the sash at the moment, but certain it must be in 40 to 45 lbs. range or more so I'm thinking of just ordering 2875. Any downside to doing that? What changes in the balance when specifying higher weights?

2870 39 to 42 lbs
2875 42 to 45 lbs
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Tom from SWISCO responded:
January 7, 2021

You want to be careful with that. If the spring is too strong, then you'll have a hard time closing the sash. It could even drift up on its own after you walk away from the window. It's best not to guess when it comes to this particular detail.
29" Series 380 Channel Balance
29" Series 380 Channel Balance
S380-29
$11.10
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