Multi-Function: Manicuring, pedicuring, shaping, polishing, remove callus, ect. Professional for both home and salon use. Efficient Heat Dissipation: Aluminum body takes it a efficient heat dissipation and long life-span. Quiet&Smooth: Professional quality makes it extremely quiet and smooth with slight vibration Light&Compact: Light pen-shape and compact design, easy to carry, allows you enjoy nail art at anytime anywhere. Speed Adjustable: 0-20000rpm speed adjustable and positive inversion switch to effectively treat both delicate areas and rough callus. Drill bits size is 3/32" can fit most professional electric drills.