Equip your semi to be Ready for the Road Ahead , with the Power Products 9-3/8" x 2-3/4" Fifth Wheel Air Cylinder, a crucial device that ensures fifth wheel trailers lock in place. By actuating the locking mechanism of the fifth wheel assembly, this piece is able to prevent trailers from disconnecting or rolling away. Manufactured with a pressure relief valve for enhanced safety and control. FleetPride is your First Click in Heavy Duty .