I need four springs for two windows

Hello, Andrew. This is an old style coil assembly that isn't made anymore, but we sell modern parts that should work in the same capacity. See our 15-177 pivot shoe and Series 152 coil spring. There will be a number printed on the spring band, near the screw hole, that tells you which weight rating you will need to select.

We don't sell anything quite like the retaining clip you show here. I suggest reusing this, since it looks to be in good condition.