This product mainly uses 45 # steel / 40Cr steel, YG8C cutter is made of hard alloy welding. Based on the high quality raw materials, hardness is greatly improved by high temperature quenching, which is longer than the average medium carbon steel drill. The of copper, self-centering knife tip, high-speed drilling, chip evacuation quickly; Four-slot design, quick chip evacuation, reduce wear. Used with the electric hammer, used for drilling adhesive, concrete, brick wall and other stone materials, widely used in construction, installation and other industries, it is a highly efficient professional drill. treatment: sandblasting Knife : copper plating Mode of action: deep drilling Diameter: 8PCS: 5, 6, 8, 10, 12, 14, 16, 18 mm Length: about 160MM Colour: silver-gray Material: steel Package Contents: 8 * Hammer drill Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from