3/8" Radius Brazed Router Bit 1/2" shank w/ bearing. For routing stone with wood router 40/50 grit diamond, best on marble, granite and glass 3/8" for creating small round over edge of granite or marble slabs. Diameter: 1-1/3" 1/2" Shank, 1-1/3" length, to be used on conventional wood routers. Use wet or dry. Water or other cooling agent is recommended for longer life of the bit. Bottom stop bearing keeps the bit from cutting into the granite.