Comes with two easy-to-set cutter wheels for quick cleaning of grooves. Heavy coil spring holds cutter in groove . Handles pistons 2 3/4" to 5" diameter Clean those piston ring groove before installing new rings! Carbon deposits in the grooves may damage piston, rings or cylinders if not removed. Heavy coil spring holds cutter in groove for fast removal of carbon. This tool comes with standard 24020 cutter blade sizes: 5/64", 3/32", 1/8", 5/32", 3/16" and special 24350 cutter blade with sizes: 1.5mm, 1/16", 1.75mm, 2mm, and 1/4". It Handles pistons 2 3/4" to 5" diameter. Handy to have around when it comes to cleaning piston rings.