USB Cordless Engraving PenThis update engraver pen is rechargeable, come with USB cable. It can be used cordlessly for more than 90 minutes after a full charge, more powerful and easily helping you to accomplish better engraving process. 30 Engraving BitsIncludes 30 high carbon diamond bits. These bits are sufficient for engraving, carving, sanding, polishing, etching, routing, grinding, drilling, and cutting. You can carve intricate details with ease, and the lightweight and compact design allows you to complete complex jobs effortlessly. LCD Display Speed AdjustmentThe engraving machine has three speeds adjustable, speed range 10000-21000 r/min. Engraving pen is suitable for decorative or personalized processing of metal, plastic, glass, jewelry, ceramics, wood, leather and many other materials. Intelligent Protection DeviceThe engraving tool has a built-in safety protection circuit board and intelligent overload protection chip, which will automatically cut off the power supply after five seconds of blocking to prevent damage to the electric engraving pen.