Needing a replacement, window is Atrium the writing on the Channel Balance is 2830 bsi vm

Thanks for reaching out! Your window balance is a match for either the S351-29 or the S390-29 Channel Balance. To determine which of these is the correct series, you'll need to confirm the depth of your shoe.

Our 2830 stamp will support a sash weighing 16 to 23lbs.

Comparison of the S351 and S390 balance shoes.