Stamp 21 12 BSI

Question

Hello
Like others who have posted, I have a channel balance with a stamp of 21 12 BSI on it. It is a non-tilt window with 1/2" wide channels. The metal shaft is 22" long.

S390 looks like close matches however my bottom guide is not 1/2" wide it is 15/32". I was another site where they listed some as 1/2" and some as 15/32" so I didn't know how specific the measurements needed to be.

Also the weight of the window sash is 37 pounds. So would I need the 2170 option or 2175?

Attached are a few photos of the bottom guide.

Thank you

Spencer

User submitted photos of a window balance.

Paul · Accepted Answer

I wouldn't worry about that difference in shoe size. Based on your pictures, the 15-001 looks like a great match. Our Series 390 looks to be the best way to go.

Can you confirm the exact weight of your sash? If it is exactly 37 pounds without tipping over slightly one way or the other, I suppose you could use either. Usually the exact sash weight will go one way or the other, though. According to our records, your old stamp is for sashes weighing 31 through 34 pounds, so I think you should definitely double check.