Description Features: The mini electric grinding tool is small size, portable to use, offers better control Compact engraver has ergonomic tri-lobal grip and precise fingertip control Hold the engraver as you would a pencil, with either your thumb or forefinger over the button. Electrical machinery engraving pen has a 21,000 RPM Motor to engrave glass, metal, ceramic and plastic, only using two included AAA batteries Applications include engraving tools, sporting goods, toys, phone chargers and the delicate personalization of jewelry, watches and glassware. Also practical as a wood engraver, or part of a metal engraving kit Specifications: Color: Blue Material:Aluminum No load speed: 12000 RPM Collet Size: 2.35mm Battery type: 2 AAA(not include) Size: 160*15*15mm Package Content: 1x Micro Engraving Pen 1x Drill Bit Replace Tool 2x Drill Bit Using: 1.Turn on the cap and put in the AAA x 2 (not include). 2.Push Switch,and it will work. The engraver is supplied with a diamond tip which is capable of engraving any surface. (Just like:Glass,ceramics,or hardened metal the replacement bit is readily available in local hardware shop.) You also can use steel bit as an alternative but it is ideal engraving plastic,wood,and metal.