50 pcs Kit Diamond Coated Rotary Burrs Large Head Style GRIT 300 50 pcs Kit, Diamond Coated Rotary Burrs, Large Head Style 1/8" Diameter Round Shank, GRIT 300 Various shapes included, such as spheres, cylinders, bullets, needles, etc.. Fits most major rotary machines brands Use to grind glass, marble, rock or jewellery.