【USB Powered】The alarm clock does not have a battery compartment so it does not use batteries, it can only be powered by the USB cable by connecting it to the DC adapter. The memory lithium button cell (CR2025) can be replaced and it can retain the previous alarm setting, but not supply power to the clock.

【7 Adjustable Brightness Levels + 5 Levels Alarm Volume】The clock has 2 display modes that can show time/date/month/year and temperature (°C/°F). L1~L7, all lights 7 brightness levels to provide a full brightness dimmer, meet your different needs, make it bright enough for daytime and not too bright at night. You can choose a comfortable brightness for your eyes. Plus with 5 levels of alarm volume, it can be adjusted to your comfortable level. Perfect for heavy sleepers.

【SNOOZE function for 9 minutes extra sleep】Press the SNOOZE button after the wake-up alarm rings, and you will get 9 minutes of extra sleep. The SNOOZE button is designed to be any button on the back, very easy to operate. 9 minutes interval snooze can be repeated 5 times until it turns off. Press any button twice to turn off the alarm. With only 3 buttons, anyone can complete all settings of the travel alarm clock in just 1 minute. The user-friendly manual also offers all operating details. And we provide warm and friendly 24/7 customer service, and we provide worry-free 1-year replacement or refund warranty.