IWC Window Balance

Hello,

It looks like you could have either our S900 or S600 spiral balance depending on the diameter of the plastic tube on your original balance, which should be 3/8" or 5/8". Also, make sure you're only measuring the tube and not the spiral that extends from it since the length should land on an even inch. 

Lastly, you'll need to weigh the sash and follow the chart under the balance product description to choose the correct color tip option for your new balance. Thank you!