Large Step Drill Bit - The step drill bit is designed with 12 steps of drilling diameter: 6-60mm (6mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm). Unique enlarged holes, no need to change drill bits and positioning holes during use. Material - The step cone cutter is made of HSS 4241 high-speed steel and titanium coating on the surface. Anti-rust, wear-resistant and heat-resistant, longer service life. Spiral Design - 135 split point and 2-flute double-edged design ensure faster and smoother cutting, stable removal and better chip removal. Three-sided shank fits securely in the chuck of power tools and prevents slipping. Surface depth gauge makes drilling accurate. Water-cooled - For workpieces with hardness below 25°; For materials such as metal, wood, aluminum alloy, plastic plate, insulation plate, etc. What you get - 1 x Spiral Drill Bit. Recommended drilling speed 250-400 rpm. Note: All data are manual measurements, please allow 1-3 cm error; due to the difference in light and display, there may be some color difference, please refer to the actual item received.