Bulk Packaged 3.2 x 12.8 mm, 1/8 x 1/2 inch 600 Grit Flat End Cone Diamond 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.