Proflow Piston Ring Filer, Rectagular, Manual, Aluminium Base, Grinding Wheel, 120-Grit, Kit - PFEPRF02Part Number: PFEPRF02 To achieve custom ring end gap, these round or rectangular piston ring filers enable the user to file piston rings quickly and accurately. Position the piston ring firmly against the dowel pins and crank the handle to turn the abrasive wheel. These can also be bench mounted. Both models come with 120 grit grinding wheels with replacements sold separately.