5Pcs Multi-Material Drill Bit Set, LittleSmith Ceramic Drill Bits Masonry Drill Bits with Surface Coating Process, Drilling in Concrete, Brick, Glass, Masonry, Tile and Wood, 6-12mm (1/4", 5/16", 3/8"HIGH QUALITY ALLOY CUTTING HEAD: the drill bit is made of cemented carbide, and its hardness is higher than the ordinary drill bit. The cutting resistance is small and the drilling EFFICIENCY is high. U TYPE DRILL BODY : drill has been slotted, the surface of the drill body is clean and NO burr, the paint is treated to prevent rust, and the chip removal is more smooth. ANTI SKID TRIANGULAR HANDLE: a unique triangular shape of the handle, so that the