USB Wireless Engraving Machine: These engraving tools can be charged via USB interface. Wireless use can idle for up to 30 minutes after full charge. Easily help you complete a better engraving process. Visible Speed ??Adjustment: The metal engraving pen is equipped with a high-quality motor. 3 gears adjust the speed, ranging from 5000-25000 r/min to adapt to different situations. The lowest speed allows you to polish nails safely, and the highest speedcan also be used for metal engraving. Various Grinding Bits: These metal engraving machine kits include 30 rotary drill bits, 2 drill bits, 3 saw blades, all of which are enough for engraving, carving, sanding, polishing, etching, planing, grinding, drilling, cutting. Start Engraving Art Now: These portable and compact etching pens are convenient to carry around, allowing you to enjoy a relaxing hand drill jewelry making time. It can work on metal, glass,ceramics,leather, wood, jewelry, stone or statues.