Window balance coil spring

Thanks for writing in! Your coil shoe resembles our 15-180 Coil Balance Shoe. I am confident this is the replacement you'll need but be sure to carefully look over the dimensions and compare them.

Alternate image for 15-180

This shoe is compatible with the Series 190 Coil Balance, secured to the shoe using the 33-073 screw. Since your sash weighs 8.5lbs, I suggest using the S190-440 coil balance. 

I noticed your existing set up does not appears to have the support clip but the compatible clip is the 15-186 Coil Balance Clip used along with the 15-182 Balance Bushing.