Simonton windows balance assembly replacement

Thanks for posting. This pivot shoe looks like our 15-192, which uses our Series 170 and Series 171 Coil Springs. They no longer make a 10 lb spring, as your stamp seems to indicate; but you can use the S170-405 5 lb Spring and S171-405 5 lb spring in tandem which equals 10 lbs of support. The Series 171 is used atop the Series 170. The video below goes into more detail.