Manual Ring Filer with 120 Grit Grinding WheelTo assure proper piston ring end gap, the piston ring filer enables the user to file piston rings quickly and accurately. Position the piston ring firmly against the dowel pins, crank the handle to turn the abrasive wheel. Using a feeler gauge, file the piston ring to meet the manufacturer's specification. Manu al Operated Model Comes with One 120 Grit Grinding Wheel Made from High Quality Aluminium Uses Proform Part #66786 Replacement Grinding Wheels