Quick chip removal without burning the drill to prevents chip blockage, easy hole opening, accurate hole opening without easy misalignment to prevents chip blockage, easy hole opening Waterproof, rust resistant, high-temperature resistant, nitriding process extends the life of the hole opener, and easily penetrates various wall Three edges drilling is easy, with low cutting resistance and efficient drilling The alloy welding is firm and not easy to lose teeth, increasing the welding area and effectively extending the life of the Drill Bits Highly concentric drilling that is not easily swaying Special hole opener for wall air conditioning, can be used directly without adding water, with powerful sharpness and the ability to drill 300 holes, Manufacturer: LIzogli