USB POWERED & USB ADAPTER - Comes with a USB cable and a USB adapter. Power supplied by USB cable, convenient to access to any USB port like computer, USB plug or even power bank. With the USB adapter, it can directly connect into a wall outlet to work. FREE BRIGHTNESS SETTING - Stepless brightness control from 0-100% allow you adjust Illumination freely and combine with setting memory enable next time turn on reach the same brightness. SENSOR CONTROL - Touch sensor Switch Design , turn on/off and brightness control easily just by slight touch.