This is a Series 210 replacement constant force balance system for tilt windows. It moderates the operation of your window sash using a specifically calibrated coil spring that allows the window to stay open when raised and remain shut when closed.
This balance comes complete with a pivot shoe, coil spring, and coil spring cover.
The spring is stainless steel and coated for low friction and corrosion resistance.
A pair of 6 lb assemblies will carry 11 to 12.99 lbs, (sold individually). The weight you need should be indicated as a stamp or imprint on your old balance cartridge cover.
Good Idea!
Balances are sold individually, however, it is a good idea to replace both window balances at the same time. Pairing a new balance with an old one would cause the new balance to wear out faster.