Bulk Packaged 2.4 x 11.7 mm, 3/32 x 29/64 inch 240 Grit Cone 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.