SMT Rechargeable Electric Engraving Pen Mini-polishing Machine 1.High universality: within the scope of any 3.5mm shank diameter drill bitgrinding head 2.High precision, cordless the portable - with the battery, and then do not have to pull the wires t 3.Power display - Host Central has a green power indicator, how much electricity can be judged accor 4.Large-capacity lithium battery - the battery with enough capacity 2400mAh lithium battery 5.Intelligent charging - with a single lithium smart charger, not afraid of overcharge, fully charge