Electric Grinder Pen Drill do grinding, polishing and engraving silver Description: Suitable do engraving and grinding materials such as wood, stone, handicraft, etc. 1-adjustable, adjust the speed in the range of 5000-10000-18000RPM for optimal control and performance. 300mAh lithium batteries, pure copper motor, protection, USB charging port, support fast charging. 20 pieces of different polishing tips do carving, polishing, cutting and polishing many materials, allowing you to effectively perform various craft work. Portable and lightweight design, easy to handle and wear anywhere. Specification: Material: ABS Mounting range: 2,35 mm Clamp sleeve depth: 25 mm Speed: 5000-10000-18000 rpm Display Built-in Power: 10 in Battery: 4,2 V 30OMAH battery capacity Size Chart: about. 120x16mm or 4,72x0,63 in. The package includes: 1x electric grinder 1x USB cable 20x grinding bits Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.