Long Use Time -100 Days USB Powered and Built-in Battery. When the charging indicator light is off, which means it is fully charged and can be used for 100 days. Helping you solve the power failure and battery troubles at one time by the green and environmentally friendly way. Smart Night Light Kids Alarm Clocks Digital alarm clock built-in light sensor. When the environment gets darker, it will emit a soft light, making it easy for you to read the time, but it will not interfere with your sleep. If you need more brighter light, pressing top light button to use nightlight, which will lasts for 6 seconds. Snooze Mode Click the TOP SNOOZE button to take a nap. You can easily turn off the alarm without opening your eyes, allowing you to get 5 minutes of lazy bed time. If you don't press the button when the ringtone sound, the ringtone will last 1 minute and then turn off automatically, beside the sound and frequency will gradually increase, the wake-up effect is better, which is very suitable for heavy sleepers. Calendar & Temperature Large Display Large numbers, 85dB loud alarm, it shows the time, date, month and indoor temperature clearly. The buttons on the back are very clear and self explanatory, so it's very easy to do. 12/24 hour format and F / C unit can be switched. Note: Only one alarm can be set. The temperature shows you room temp rather than general weather.