This product is made of high speed steel material. Smooth surface finish, long service life. Suitable for wood, malleable iron, aluminum, plastic etc. Great replacement for your dull drill bit to improve work efficiency. Straight shank design is more suitable for many electric drills (here is not included). This High Speed Steel Drill Bit Set features 5 different drill bits in the following shank diameter sizes to meet most of your household Do-I-Yourself needs:1, 1.5, 2, 2.5, 3mm Specification:Material: High Speed SteelSurface Treatment: Titanium CoatingShank Diameter: 1mm/0.04-inchTotal Length: 34mm/1.34-inchCutting Edge Length: 14mm/0.55-inchShank Diameter: 1.5mm/0.06-inchTotal Length: 40mm/1.57-inchCutting Edge Length: 17mm/0.67-inchShank Diameter: 2mm/0.08-inchTotal Length: 48mm/1.89-inchCutting Edge Length: 22mm/0.87-inchShank Diameter: 2.5mm/0.1-inchTotal Length: 57mm/2.24-inchCutting Edge Length: 29mm/1.14-inchShank Diameter: 3mm/0.12-inchTotal Length: 60mm/2.36-inchCutting Edge Length: 32mm/1.26-inchPackage Content:- 1 Set x High-Speed Steel Twist Drill Bit(each size 10pcs,total 50pcs)Notice:Please keep cool and gentle using, the working life of the twist drill bits can be largely prolonged by proper usage.