*Material: 4341 High Speed Steel,Made of High Speed Steel (HSS), high hardness and rust resistance for long service life. *Size: M3x0.5, M4x0 .7, M5x0.8, M6x1, M8x1.25, M10x1.5. 6 sizes set, which perfectly meet your different needs. A sharp, the drill bit induction hardened, resistant to slightly induced wear, to ensure the puncture speed, improve work efficiency. *Complete drilling, tapping, deburring and countersinking in one operation save processing steps and time costs, improve working efficiency. * 6 steel drill bits, suitable for drilling wood, plastic, fine copper, aluminum and other soft metals (5-6mm), not for hard materials (eg sheet steel). *When drilling a hole, you need to inject water at the same time to cool the bit. This will help you increase the value of the exercises. If you cannot cool the drill bit when drilling holes, the drilling speed should not be too high, and you should not drill too frequently.