Intelligent Power-Off Protection: Rechargeable USB type-C charging metal engraver pen, there is a built-in overload protection chip, when the resistance is too high, it will automatically power off to protect it, and prolong the service life of the jewelry engraving machine 3 LEVAL VISIBLE SPEED ADJUST: This electric engraving pen for all material is about 5000-18000r/min, and different speeds are used to engrave different materials. The engraving pen is lightweight and ergonomically designed to give you precise control and engraving. Low Noise: The sound of this cordless rotary tool is very low when working, even if someone is sleeping, he or she will not feel very noisy. Great for beginners and professionals to use anytime, anywhere to make unique creations that you like This engraving machines kits include 30 engraving bits, 3 saw bits, 1 connecting stick, 3 drill bits, 1 polish bit, 16 stencils, and 1 USB charging cable, all these bits are enough to work on engraving, carving, sanding, polishing, etching, routing, grinding, drilling, cutting.