Mini-style battery-powered electric engraving pen Press and hold the white button rotation, release the button to stop the rotation, very easy to use Diamond turned, impact resistance, high strength, high wear resistance Very convenient engraving on metal, glass, clinker, wood, horny material,Jade, plastics, ceramics, olive stones, stones, aluminium products, glass tubes, silver ornaments Small size, very lightweight, so easy to carry Use battery-powered, operating occasions unrestricted, grinding idling about 90 minutes