Traco NX-540 single hung tilt coil balance

Hello,

We can't be sure with the balance parts still installed but you may be showing the 15-150D coil spring nylon cover. If so, the coil springs used with this cover is the 1/2" wide S160. There should also be stamps on the end of the old spring once they are uninstalled. 

We will need to see your pivot shoe fully removed from the window to compare to our inventory. See the videos related on this page to help you through the process. Thank you!