- Professional step drill bit 10-45 mm, with 8 diameter levels (10, 15, 20, 25, 30, 35, 40, 45 mm) - Made of high-hardness HSS 4241 steel with titanium coating for maximum durability - 12 mm stepped shank, compatible with most electric and bench drills - 135° split point tip and double flute for self-centering, deburring, and efficient chip removal - Allows pre-drilling, drilling, and deburring in a single step, optimizing work time - Suitable for drilling mild steel, non-ferrous metals (aluminum, copper, brass, zinc), plastic, and wood - Not recommended for stainless steel; for that, a cobalt alloy drill bit is required - Industrial polishing ensures clean and precise cuts with every use - Includes deep laser scale for quick and accurate diameter reading - Water cooling and a speed of 250-400 rpm are recommended to extend the drill bit's lifespan