MAGNETIC CHARGING BASE: when you put engraving pen on the charging base,it will be easily and accurately attracted on to charging base by the magnetic force for charging. The high-capacity 350mAh battery provides extended use to 40min. REVERSE/FORWARD ROTATION: Compare with other engraving machine, our metal engraver has 2 directions rotation. 3 SPEED ADJUSTING:Metal engraver pen equips with qualify motor. 3 position adjust rotation speed from 5000-18000 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. RICH ACCESSORIES:these metal engraving pen kit include 30pcs rotary diamond bits,10pcs metal card blank,3pcs stencils. It help you create an unique personalized business card. It can work on metal, ceramic, leather, wood,jewelry,stone or statue.