Material: High Speed Steel (HSS). Diameter: 0.5mm – 14mm. Features: Full-grinded drill, sharp, wear-resistant and durable; accurate positioning; good chip removal; high drilling efficiency ect. Scope of application: commonly used in the processing of stainless steel, die steel, cast iron, aluminum, copper, steel, wood, plastic and other materials. This drill bit works with alloyed and non-alloyed steel, stainless steel, cast iron, cast steel, acid-resistant and heat-resistant steels. It has a cylindrical shank system (shank equal to drill bit diameter) and is intended for use in drill stands and drill drivers. The HSS Twist Drill Bit Cobalt is Type N (flute angle) with a 135-degree tip and a diameter tolerance of h8. Active cutting and perfect centring without wandering are achieved by the pointed split-point tip. HSS Twist Drill Bit Cobalt provides long-lasting performance when drilling stainless steel. Note: Do not use on tiles, concrete, wall, stone ect. Please list your special requests color, packages, etc. (15-35 Days to Delivered). Please contact me before you return it. Not accept returning of electronic components. Feedback is very important to us.