Features: 1.Engine Valve Grinding Tool: The engine cylinder head valve lapping tool provides the easiest and most efficient way to lap your valves, restore the running effect of the engine. 2.Function: Grind the valve to make the port and the valve plane contact closer, valve leakage will cause insufficient cylinder pressure, the engine lack of cylinder work, weakness. 3.Material: Made of carbon steel, it has high strength and rigidity, and can withstand high temperature, high pressure, impact, lubrication difficult work requirements. 4.Perfect Configured: With speeds up to 3000 rpm, a hose bore of 10 mm, a 1/4in air intake, and a 3.53CFM air consumption, work efficiently and quickly. 5.Package Includes: The package includes four rubber suction cups in sizes 20mm 30mm 35mm 45mm and a toolbox for the perfect storage of the grinder. Specification: Item Type: Engine Cylinder Head Valve Grinder_x000D_ Material: Carbon steel_x000D_ Rotational Speed: 3000 rpm_x000D_ Hose Inner Diameter: Approx. 10mm/0.39in_x000D_ Air Intake: 1/4in_x000D_ Working Pressure: 90 PSI (6.3 BAR)_x000D_ Air Consumption: 3.53CFM (100L/MIN)_x000D_ Four Rubber Suction Cup Sizes: Approx. 20mm/0.79in, 30mm/1.18in, 35mm/1.38in, 45mm/1.77in Note: This equipment does not rotate the shaft, only plays the role of entering and exiting