1. Straight round shank. 2. M35 high speed steel with cobalt, super hard. 3. Smooth to reduce friction, blade for fast drilling hole. 4. Wear-resistant with long service time. 5. Perfect for drilling metals and wood, such as: aluminum, iron. Suit to use with hand drill chuck, bench drill, radial drill etc. Coating: Titanium Coated Diameter: 1.5mm, 2mm, 2.5mm, 3mm, 3.2mm, 3.5mm, 4mm, 4.5mm, 4.8mm, 5mm, 5.5mm, 6mm, 6.5mm Shank: Round Application: steel, iron, aluminum and other metal pipes job openings. Material: high speed steel colour: As shown Package Contents: 13 x steel twist drill bits 1 x Center Punch Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.