hydraulic cylinder with all kind size and mounting type, for tower crane 1. Mounting type: trunnion, flange, earring, according to your demand; ... world so that you the hydraulic cylinder can seal better;3. Piston rod: 20#, 45# steel;with high frequency quenching;4 ... world so that you the hydraulic cylinder can seal better;3. Piston rod: 20#, 45# steel;with high frequency quenching;4 ...