I need replacement parts for feldco windows

Hello there. I believe this is a 15-181 Double Support Clip and 15-182 Balance Bushings. These parts work with Series 190 Coil Balance springs, which usually attach to a 15-180 Pivot Shoe. If you are replacing the coil springs, you need to choose 'spring weights' for the replacement springs. These designate the weight each individual spring can support. Stamps on the old springs can indicate what spring weight to choose--but if there are none or you are unsure, give me the exact weight of the window sash this system supports, and I can calculate it for you.

If the window weighed exactly 25 pounds, you could use (4) of the S190-640 6 pound springs, a pair for each side of the window sash. That would give you 12 pounds of support on either side, for a total support of 24 pounds--being within 1 pound of the exact weight works just fine. However, it's crucial you get an accurate reading of the sash weight as possible to make sure you're indeed within that + or - 1 pound margin or error. Let me know if you have further questions.