Making sure this is the right channel balance

Question

Hi,
I have a 14 inch channel balance marked as shown in the picture (13 3 GK CALDWELL). There are two of them, and I think they are the S380 series, 14" 1320. The sash weight on my bathroom scale is about 7 lbs (but it's not a very good scale... If the markings indicate different, I'd believe the markings)

Tom · Accepted Answer

What's the depth of the shoe? If it's 1", choose Series 380. If it's 1-3/32" or so, choose Series 385. If the 7 pound measurement is correct, choose 1320. The markings indicate 1330, but your best bet is to weigh the sash removed from the window and trust the weight you get. 1330 is stronger, and 1320 is weaker.

Comparison of 15-004 and 15-005