No names or numbers on the parts

Thanks for reaching out! Your pivot shoe looks like it could be the 15-177 Coil Balance Shoe. To confirm that this is the correct replacement, look over the dimensions and design to confirm that this is the right fit.

Alternate image for 15-177

This shoe is compatible with the 1/2" thick Series 152 Coil Balance spring. Since your window weighs 18lbs, you'll need the S152-9 Coil Balance. You'll need to secure the coil to the shoe using the 33-072.

If you are looking to replace the existing balance support, you'll need the 15-143 Coil Bushing, the 15-144 Coil Bushing Cap, and the 15-145 Coil Support Barrel.