Hello, thank you for posting,
Your pivot shoe resembles the 15-141 style, but the compatible coil springs have been discontinued. Instead, we recommend converting to the 15-140 pivot shoe that is compatible with the Series 150 coil springs. Review the dimensions below! If you cannot reuse your original covers, please review the 15-143 bushing, 15-144 bushing cap and 15-145 support barrel.
For the 16 pound sash, you can double up and use (2) S150-4 on each side or switch to a single assembly and use (1) S150-8 on each side.
For the 10 pound sash, you can use (1) S150-5 on each side. Please review and let me know if you have any additional questions.
