The package contains only 6 Materials: 4341 high speed steel, made of high speed steel (HSS), high hardness and long anti-rust life. * Size: m3x0.5, m4x0.7, m5x0.8, m6x1, m8x1. 25, m10x1.5. 6 sets of sizes to meet your different needs perfectly. Sharp, induction-hardened drill bit, resistant to slight induction wear, ensuring punching speed and improving work efficiency. *Complete drilling, tapping, deburring and countersinking by one operation, save machining steps and time costs, and improve work efficiency. *6 steel drill bits for drilling wood, plastic, fine copper, metal aluminum and other soft metals (5 - 6 mm) and not for hard materials (such as steel sheets). * When drilling, water should be injected at the same time time to cool the drill bit. This will help increase the value of the exercise. If it is not possible to cool the drill bit during drilling, the drilling speed should not be too high and the drilling should not be frequent.