Note Completely soak your feet first to soften the keratin: Soak your feet in warm water for about 10 minutes. If the calluses are thick, use 2-3 spoons of white vinegar + hot water to soak your feet. Keep your feet dry before using.Exfoliation should not be too frequent: use 1-2 times a week. It is not recommended to polish all dead skin calluses at once.Please completely charge it for the first use.The body is not waterproof and cannot be washed Specification Built‑In Battery Battery 1200mAh Charging Time DC 5V Charging Current 2A Rated Voltage 3.7V Rated Power 2.5W Use Time 50min Low Level Speed About 1600 rpm High Level Speed About 1700 rpm Package List 1 x Host (With 1 Dark Sanding Head) 1 x Gray Sanding Head 1 x Blue Sanding Head 1 x Filter Sponge Clamp Circle 1 x USB Charging Cable 1 x Manual 1 x Cleaning Brush