The US Pro 5-35mm Nitride Coated M2 Step Drill is designed for superior performance and durability. Its nitride coating and heat treatment enhance abrasion resistance and hardness, making it ideal for various materials. Size Range : 5, 7, 10, 12, 15, 17, 20, 22, 25, 27, 30, 32, 35mm Material : Premium M2 high-speed steel Coating : Nitride coated for increased abrasion resistance and long service life Heat Treatment : Increased hardness for extended tool life Shank Diameter : 13mm Shank Style : 3 flats for secure grip Shank Length : 24mm Overall Length : 63mm