Window Balance for non-tilt window

Question

Hi,
I am looking to replace the window balance on 2 windows. Window one has the marking 2120 B.S.I and the second window has the marking 21 3 BSI. The top and bottom of the balances are identical. The windows are the same height of window and sash, the only difference is the width: window 1 is 21", window 2 is 27". The measured length of the metal part is 22". I already found a web site that states that the first two digits of BSI balances is the length - 1" (which matches for my window) and the 2nd pair of digits is the weight rating. 20 lb would make sense for the 1st window, but not sure why there is only a "3" on the second window'w balance. Attached are the pictures (all from window 1, expect img_3151 and img_3154 are from the 2nd window.
Looking at the product selector on your web site it seems that "Product Code: S350-22" is the closest fit. Would you agree?
Window 1 would be load 2120 as marked and I am guessing 2130 should be appropriate for window 2.
Would be great if you can confirm/correct my assessments before I am placing an order.
Thanks and best regards,
Juerg

Bob · Accepted Answer

Hey Juerg. Do both sets of balances have the exact same nylon attachments? If so, see the S350-22 Channel Balance should be what you need. Review it and the specs to confirm. For a stamp option choose 2130.