Air Compressor Pump, Lubrication Type Splash Lubricated, Number of Stages 1, Maximum Output Power 4 hp, Free Air Flow Rate @ Maximum Pressure 15.1/9.9 cfm @ 145 psi, Number of Cylinders 2, Maximum Operating Pressure 145 psi, Flywheel Diameter 12 in, Flywheel Included Yes, Pump Speed 1,400 RPM, Construction Aluminum, Cast Iron, Groove Section A, Number of Grooves 1, Valve Type Reed, Valve Material Stainless Steel, Rotation CCW, Stroke Length 2 1/4 in