Bulk Packaged 3.8 x 10.5 mm, 5/32 x 13/32 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.