Oilless Diaphragm Vacuum Pump Industrial Oil Free Piston Vacuum Pump 550w 110v Usa. High Efficiency: This 550w Diaphragm Vacuum Pump Adopts a Pure Copper Motor and High-quality Bearings for Stable Operation, with a Rated Speed of up to 1440 Rpm and a Vacuum Flow Rate of 67l/Min (2.4cfm).