High Quality Materials: Made of high quality titanium coating ensures extreme durability, reduces co.ukiction and heat. Professional Step Drill: Professional design Step Drill for drilling holes of various sizes co.ukom 5mm to 35mm in diameter, optimum speed and precision. You can work large size holes without having to replace the drill bit and locating hole. Laser size: The dimensions are laser engraved into the metal so that they do not wear out even after repeated use. Step Drill: mainly for processing wood and steel drilling, including metals, aluminum, wood, plastics etc. Tips: drilling, bench drill. Working by water cooling, can effectively extend the service life of the drill bit. Step Drill Bit ， Step Drill Bit (5mm-35mm) Triangle Conical Titanium with Titanium Coating, for Screwdriver Drilling on Steel, Brass, Wood, Plastic