Material: 4341 High Speed Steel, made of high speed steel (HSS), high hardness and rust resistance for longer service life. Size: M3x0.5, M4x0.7, M5x0. 8, M6x1, M8x1.25, M10x1.5. Set of 6 sizes, perfectly meet your different needs. A sharp, induction hardened drill bit, resistant to wear easily caused to ensure the piercing speed and improve work efficiency. Complete drilling, tapping, deburring, etc. Countersinking in one operation saves processing steps and time costs, improves work efficiency. 6 steel drill bits, suitable for drilling wood, plastic, thin copper, aluminum and other soft metals (5-6mm), not for hard materials (such as steel sheet). When drilling a hole, you should inject water at the same time to cool the drill bit. This will help you increase the value of the exercises. If you can't cool the drill bit when drilling holes, the drilling speed should not be too high and you should not drill too frequently.