Hydraulic Pump Body - Smooth surface, excellent sealing, and no oil leakage. Pressure Relief Valve - A pressure relief valve is located on the pump head; it must be tightened clockwise during operation and loosened counterclockwise to release pressure. Oil Pipe and Quick Coupling - The CP-700 hydraulic pump is equipped with a 1.8-meter-long oil reservoir pipe and a ZG 3 8 threaded quick coupling. Vent Nut - An indicator is located at the end of the pump body; this nut must be loosened during use to prevent the oil tank from sealing. Wide Applications - This hydraulic pump can be used in hydraulic punch presses, hydraulic cutting machines, hydraulic jacks, hydraulic clamps, etc.