Window coil spring replacement

This looks like a 15-199 Pivot Shoe, which uses either the 3/8" thick Series 165 springs, or the 1/2" thick Series 160 springs. Please measure the thickness of your old coil springs to determine which you need. 3/8" springs stamped with a '4' should be our S165-4 4 pound springs. If this is what you have, you can also use the 15-205 Triple Support. Let me know if you have the 1/2" springs instead, or fi you have any other questions.