The head bit is suitable for sink cutout and round cutting on corner and edge. This is made of a soft diamond bond. Use: WetApplication: Granite, Engineered Stone, MarbleMachine: CNC machineArbor: M12 or M10Max RPM: 4,500Tip: 20mmCNC Head BitAvailable Options Diameter (inch) Diameter (mm) Tip height (mm) 3/4 20 15/20/40 1 23 20