DeWalt QZ Extreme 2 Metal Drill Bits - 49-151mm (Pack of 10) - DEWALT DT5551-QZ, These 7.0 x 109mm drill bits from DeWalt have been manufactured to a very high standard courtesy of the innovative tapered web which greatly reduces breakage, while the gold ferrous oxide coating prevents overheating for longer bit life. Whether you are a profressional tradesman or DIY enthusiast, the drill bits are ideal for portable drilling of steel, alloyed and non-alloyed up to 900N/mm2, and for drilling a sheet or thin materials (suitable for use in wood and plastics). The metal tip starts drilling on contact for clean, accurate holes, while the bit itself has a no-slip shank with 3 flats, eliminating slipping in the chuck (diameters 5mm and above only). DEWALT DT5551-QZ Extreme 2 Metal Drill Bit 7.0 x 109mm (Pack Of 10).