Rounded Brazed Finger Bit 1/2" shank Long. For routing stone with wood router 40/50 grit diamond, best on marble, granite and glass Diameter of diamond bit: 23mm or 11/12" Total length: 3-3/16" Height of diamond: 1-3/4" 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.