3.【Two-speed speed regulation】： Press the switch to display the green light I is the first low-speed gear, choose II as the second-speed high-speed gear, and select the speed according to your own needs. 4.【USB battery & dust-free design】: Battery with 1000mAh capacity for long operating times. It can be connected to a PC, adapter, power bank, etc. for charging. Our callus remover is motorized with a built-in vacuum cleaner and can absorb most dust when you rub your feet. Don't worry that the dead skin will be scattered and difficult to clean 5.【 Waterproof & Ergonomic】:The callus removal can adapt to all kinds of humid environment, you can enjoy foot care in the bathroom, do not submerge it in water. A perfect gift for your family and friends. Special ergonomic, non-slip design, you don't have to worry about falling.