Channel balance

Thanks for writing in! Your channel balances appear to be either the the S351-24 with a 1" shoe or the S390-24 with a 1-1/8" shoe. To determine which series is needed for your window, look over the dimensions from the diagram below to confirm the depth of your bottom shoe. You'll also want to be absolutely sure that both attachments are wingless.

Comparison of the S351 and S390 balance shoes.

Since your balance is stamped with a 23 4, you'll need to select the 2340 stamp option which can support a sash weighing 18 to 23lbs. Although, you mention that you were looking at the 2250 stamp option on the 23" balance. This can support a sash weighing 23 to 27lbs. 

If your sash weighs more than 27lbs, I'll need to know the exact weight of your sash to determine the correct stamp option for your balance.