High-quality materials: Our step drill bit is made of high-speed steel and provides fast, comfortable and frictionless drilling; Titanium coating: The peeling drill bit with titanium coating has good resistance to corrosion, heat and rust; reduces friction and heat; for a longer service life even at extreme temperatures. 13 drilling sizes: For different hole sizes, you only need one step drill bit; 13 sizes are on the step drill bit for your convenience : 5mm, 7mm, 10mm, 12mm, 15mm, 17mm, 20mm, 22mm, 25mm, 27mm, 30mm, 32mm, 35mm. Fast Drilling: Double blade design provides faster and frictionless cutting. Please note that during the working of the step drill, pour some water to cool the step drill; the service life of the HSS step drill will be effectively extended. Material: The cone drill bit is suitable for household repairs and light work such as drilling holes in plastic, copper, aluminum and many other types of sheet metal; but not suitable for stainless steel. Features: The HSS