Description : High quality material. High quality alloy is used as raw material. The n oxidation process of the cutter is determined by the hardness of the drill. Surface electrophoretic coating process Fully polished and anti-rust treatment, clean and sharp, no burrs. The drill is more wear-resistant and durable. Fully automatic polishing: cnc polishing is fully automatic and every one is uniform. Unique bevelled design Low cutting resistance, stable drilling characteristics, fast speed and no broken edges. Clean and smooth opening, no broken edge, no fluctuation, easy to break. Width of use Professional glass and tile drill bits provide smooth and precise drilling on tiles, marble, thin iron sheets, mirrors and glass. Remember to add water or soda when drilling. Can be fitted into general electric hand drills and table drills. Machine drill clamping range of 10mm or greater Specifications. Material: Carbide Colour: Brown Tool shank: 1/4 Hex Dia: 3mm, 4mm, 5mm, 6mm, 8mm, 10mm, 12mm Package Contents: 7* Drill Bit