USB WIRELESS ENGRAVER:This engraving tool equiped with Lithium battery and rechargable by USB interface. Cordless using will be up to 30 minutes idling after full charge VISIBLE SPEED ADJUST:Metal engraver pen equips with excellent motor, power up to 25W while working. 3 position adjust rotation speed from 5000-25000 r/min to apply different situations. The lowest speed will let you polishing your nail in safe, the highest speed are also working on metal carving VARIOUS GRINDING BITS: this metal engraving machine kit include 30pcs rotory bits,2 drill bits, 3 saw blades, all these bits are enough to work on engraving, carving, sanding, polishing, etching, routing, grinding, drilling, cutting BEGIN ENGRAVE: this portable and compact engraving pen are convience to take anywhere you want and allow you enjoy relaxing hand drill jewelry making time. It can work on metal, glass, ceramic, leather, wood,jewelry,stone or statue BEST CHOICE FOR BEGINNER:This metal engraver set is easy to operate,special for beginner to use.Create a keychain,DIY a necklace or make gift with this kit