Coil balances

I have tilt-in vinyl windows with these coil balances. One picture shows the cover removed from the top (fixed) coil roller. The coil itself has "740" stamped into the metal. No other markings exist. The assembly is in good shape. Only the coils themselves are broken. It looks like tbe coils attach to the lower (moving) part of the assembly with a screw as shown. These pictures are from another window of the same system that is not broken.