Windows part

Your old shoe looks like our 15-180, which is designed to be compatible with the Series 190 spring, 15-181 clip, and 15-182 bushing. Let me know if you had any questions about these parts.

If the window weighs exactly 15 lbs, I'd use a S190-840 8 lb spring and S190-740 7 lb spring on both sides of the sash. This equals 15 lbs of support on both sides, for a total of 30 lbs of support overall. 

All items can be bought right through our online store.  When you find a part you want, simply click "Add to Cart," and then click "Checkout" at the top right hand corner of the screen. Don't forget to set the quantity!