Rounded Brazed Diamond Router Bit 1/2" Shank Medium. For routing stone with wood router 40/50 grit diamond, best on marble and softer granite Diameter of bit: 23mm or 11/12" 1/2" Shank to be used on conventional routers. Use wet or dry. Water or other cooling agent is recommended for longer life of the bit. Total length: 2" Length of diamond: 23mm or 11/12"