MIBRO 12-Piece Rotary Masonry Drill Bit Set. Ideal for rotary drilling into brick, asphalt, dry or damp concrete and cinder block. Set includes 12 bits with duplicates and triplicates of the most common sizes. Each bit uses premium, micro grain carbide and is nickel-plated for corrosion resistance. The drills have wide in. slow spiral in. flutes that allow for efficient debris removal, even when the material is damp. Drills feature a 3-flat shank, ensuring a secure grip in the drills chuck. Patented, heavy-duty MBX case has molded rubber corners for hard impact protection.