Bulk Packaged 2.9 x 11 mm, 7/64 x 7/16 inch 150 Grit Flame Diamond Coated Burr, 1/8 inch shank. For use with Dremel Rotary Tools. Diamond coated accessories will cut into glass, wood, metal, stone, practically anything. For longer life, use with a cooling agent such as Eurotool Cut Lube.