LED time display, good visual effects 12Hour Display and 24Hour Display Two time display modes. According to your habits,You can switch from one mode to the other by pressing and hold the "UP" button for 3 seconds. 3 brightness adjustment levels. To avoid the light too bright at night, the alarm clock is equipped with 3 brightness adjustment levels. Adjust automatically :The clock will automatically turn dark in night mode.The default night mode time is between 18:00 and 6:00. Adjusted manually: In the time mode, press the "UP" button to select the brightness level.The default brightness is medium. The product has a built-in CR2032 button battery. Even if the alarm clock was temporarily outage, the alarm clock still can work with the button battery, saving us the trouble to adjust the time. Power: 5V (including AC adapter), CR2032 button battery (included) used as backup, USB cable (included) Precautions: Remove the plastic insulation from the battery compartment and connect the product to electrical with the USB or adaptor. There are USB ports and AC plugs to use. And the two interfaces configuration allows us to use at a lot of places, such as desks, bedside tables, studies, living rooms, etc After-sales service: 1.If the product doesnt work within 18 months, we can offer you a full refund or a free replacement. 2.If the product doesnt work within 18-36 months, we can offer you a free replacement. 3.If the product doesnt work after 36 months, we can replace parts for free. After-sales notice: All products damaged due to external force are not in the policy. For example, the product is dropped and broken, or the product is crushed and so on. Packing List: 1 8888 LED digital alarm clock 1 USB cable 1 AC adaptor