Spring returns

Looks like you need a new spiral balance. This appears to be a fairly typical tilt window, so there are only two options: either the 3/8" diameter Series 900 or the 9/16" diameter Series 600. You'll have to measure the diameter of the outer tube to verify the better match.

I'm not sure what the window attachment might be in this case, that term could describe a lot. based on your photos I'm going to assume it's the pivot shoe; that's the connection point between balance and sash that also enables the sash's tilt action. Is that the part you need?

We sell a ton of these, so I'm confident we have a good option, but I'll need you to remove the original and measure its width" x thickness". That will allow me to find you an adequate replacement.