Selecting the correct spiral window balance

I think you might want to consider our S900-23 spiral balance. Just double check your measurements. Make sure when measuring the length and diameter that you're only measuring the outer tube.

I'm not sure what tip color you need. You will have to weigh your window sash and compare it to the weight ranges shown for the S900-23, or whichever size balance you choose to go with.

The rule of thumb is to replace your balance with exactly what was installed originally. Your case is a little different, though, so it's hard to say. Balances usually come in lengths that end on the inch. It's not common that they have an uneven length like yours. I think Dave is right in this case, and that you should use a 23" long balance.