Master Mechanic, 38 x 13, Rotary Percussion, Carbide Tipped Masonry Drill Bit, Black Oxide, Standard Shank, Beveled Edge, Negative Point Provides Faster Penetration When Used With Hammer Drill Or Drill In Percussion Mode, Black Oxide Surface Finish With Deep, Heat Treated Flutes, Recommended For Drilling Cinder Block, Common Hard Brick, Plaster, Ceramic Tile, Glazed Tile Wet Or Dry Concrete, Moderate Use In Marble, Granite Concrete Over 6000 PSI, Carded