Master Mechanic, 5/16" x 6", Rotary Percussion, Masonry Drill Bit, Black Oxide, Carbide Tipped Designed For Use In Drills With Rotary Or Hammer Mode, Recommended For Drilling Cinder Block, Common & Hard Brick, Plaster, Ceramic Tile, Glazed Tile & Wet Or Dry Concrete & For Moderate Use In Marble, Granite & Concrete Over 6000 PSI, Carded.