What Channel Balance is this?

Question

Hi, I have to replace theses balances stamped 27 4 NK BSI. Not 2740, just 27 4.
I tested resistance of one balance on a scale it seems like it will hold up 4 pounds. At the point the balance started to release and recoil into the sleeve, the scale read 4 pounds.
Can you reccommend an equivalent. The bottom shoe is 1 3/32" wide. so far the 28" series 385 looks the closest. The metal channel is 28" long. Thank you!!!
Is BSI a brand??

Paul · Accepted Answer

Many thanks for writing in to us. Judging from your photos, your balance's nylon attachments lack wings, so the S390-28 Channel Balance would be a better choice. The bottom shoe is 1-1/8", but your old balance shoe might be worn down from use. The stamp option is determined by the weight of the window sash, not by weighing the balance. 27 4 conforms to our stamp option of 2740, which will hold a window sash in the weight range of 19 through 26 lbs.