Built-in USB rechargeable power bank: USB charging cable included for power supply (without adapter) and built-in lithium-ion battery, the inner clock ensures long standby after fully charged.Built-in battery backup to save charging clock settings in the event of a power outage.(Note: Please use usb port for connection or only 5V/1A and 5V/2A adapter to charge the clock)6 Levels Adjustable Nightlight Silent Button, This digital alarm clock has 6 levels adjustable ambient lights that can be activated by simply pressing the silent button.There are blind spots on the buttons that can be easily found and configured even in the dark.Memory function powered by power supply, this digital alarm clock is powered by power supply only, and the built-in battery retains memory of all settings during power outage.The power-operated bedside digital alarm clock includes a universal 100V - 240V power adapter that can be used almost anywhere.Sleek and easy to use curved screen design, for this digital alarm clock, setting up is definitely a breeze that can be done in less than a minute and is suitable for children and the elderly.The modern and stylish curved screen design makes it the perfect holiday gift for children, parents or friends. if you encounter any problems