IVY Classic 10220 5/16 x 4-Inch Premium Carbide Masonry Drill Bit, 1/Card Round shank designed for rotary and percussion hammer drilling through block, brick, stone, concrete and marble, Swift Cut (Registered Trademark) Tungsten Carbide reinforced head - precision ground Induction-hardened body ensures straightness and strength, black-oxide finish Engineered with wide flutes for fast dust removal Diameter: 5/16-inch, Overall Length: 4-inch, Shank: 1/4-inch, Flute Length: 2-1/4-Inch