Coil-Rite air helper springs mount inside an existing open coil spring suspension. These air springs provide adjustable spring rates far superior to the standard coil spring. The durable polyurethane air springs will support 500-1,000 pounds per set. Coil-Rite air helper springs are made of durable polyurethane to withstand the rigors of coil-sprung suspensions. Each air spring is pressure tested before leaving the factory. Over 1/2 million cycle life test. The Kit includes air springs, air line, fasteners, inflation valves (manual inflation), supports (if required), push-to-connect air fittings and detailed instructions.