Rechargeable Variable Speed Mini Grinder Set USB Charging Electric Drill Engraving Pen Rotary Tools Kit for Polished Carving Feature 1. Multifunctional: can be used for cutting/punching/grinding/peeling/polishing/engraving/cleaning/rust removal2. Comfortable grip: as comfortable as holding a pen, with just the right radian, effort-saving pivot point, and grip like a pen!3. USB convenient charging: compact and portable, more convenient to use, and diversified charging methods4. Speed regulation function: three-gear speed regulation and one-key switch, to meet different work needs for speed regulation5. Quick installation: the copper core can be replaced, the core is accurate and durable, the concentricity is high, the spindle is easy to clamp and replace the acceories, and the clamping range is 0.5-3.2mm Grinding head installation step 1. Pre the self-locking key and rotate the head2. Do not release the automatic lock3. Insert the grinding head to be used4. Tighten the chuck cap, loosen the cap to enter the locked state, and loosen the self-locking key of the head cap. Specification product namerechargeable small electric grinderBattery voltage4.2VBattery capacity600mAhClamping range0.5~3.2mmRated speed5000/10000/15000r/minGear adjustment3 gears are adjustableProduct net weight95g