Counter balance mechanism

Hello,

Take a look and compare the specifications of the 15-177 pivot shoe to yours removed from the window. If it's a match, this shoe is used with the S152 coils springs and related supporting hardware shown on this page. Once you've removed the hardware from the window, there should be a stamp at the base of your coil springs that you would use to choose the corresponding strength options. Thanks for posting! 

Alternate image for 15-177