Color tip

Hello, thank you for posting,

It appears your window uses non-tilt spiral balances. You could either have the Series 500 with a 5/8" diameter tube or the Series 400 with a 3/8" diameter tube. 

You will need to measure the original diameter of the tube to confirm the correct series and match up the colored tip for a 30 inch length. Let us know if you have any additional questions!