5.5HP 21CFM 175PSI V Type Twin Cylinder Air Compressor Pump Head Double Stage Features: High efficiency, high precision, universal, low energy consumption. High quality material, not easy to damage. Strict balance support and correction to ensure the smooth operation of the main engine. Special valve steel is used for hair piece, which has good strength and toughness at high temperature. Faster inflation and low noise. Strong cooling blade, good cooling performance. Installation notes: 1? When placing the pump head, the motor pulley and the belt pulley must be in the same straight line. The more aligned, the less vibration. 2? Tighten the screws (including the base and pulley screws).