[Professional Tool]: Using this tool can correct irregularities and subsurface damage of the new valve,thereby perfectly fitting into the valve guide to a firm fit. [Features]: Including 4 attachable suction plates to make fitting and seating various valve sizes in your lawnmower, chainsaw, car, or motorcycle. [Instructions]: Use a thin layer of engine valve lapping compound (not included) around the valve and install the valve in valve guide, Press correct size valve suction cup tool firmly onto head of valve, and use your power drill to slowly the small lapping tool until a suitable finish is obtained.(Working Speed: 1000rpm To 1250rpm Max)., Manufacturer: Akfldms