To assure proper piston ring end-gap, the Aeroflow Performance manual piston ring filer enables the operator 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. It features a 120 grit grinding wheel which can be purchased separately ( AF59-2099 ). This piston ring filer can be bench or vice mounted whichever is suited for the operator.