No marking

Thanks for posting! Your pivot shoe appears to be an older, discontinued version of the 15-177 Coil Balance Shoe. I am confident this will work as as replacement for your existing hardware but you'll still want to remove the shoe and compare the dimensions.

Alternate image for 15-177

This shoe is compatible with the 1/2" thick Series 152 Coil Balance. This is secured to the shoe using the 33-072 screw. To determine the correct spring needed for your assembly, you'll need to remove the existing coil and look for any stamps/markings on the metal. If there aren't any stamps/markings you'll need to obtain the exact weight of the sash and divide that number of the total number of coils in the window.

You may also need the 15-143 Coil Bushing, 15-144 Coil Bushing cap, and the 15-145 Coil Support Barrel to replace the existing cover.