Rexroth Relief Valves are operated by hydraulic oil directly pushing the poppet seat movement, consists of sleeve, damping piston, spring, adjustment elements. The P port of the valve is connected to the system and T port is connected to oil tank. When the system pressure is higher than the preset pressure of the spring, the pressure oil pushes the poppet seat to open and allows oil from the inlet port P to outlet port T overflow, and obtain the normal pressure in the hydraulic systems.