2 power supply ways: (1) By USB cable (included) connect to USB port, time will display on screen all the time.(2) By 3 x AAA batteries (not included), time won't display on screen, you can press any button to activate the screen and check time Alarm and snooze: Long press "Alarm" to set the alarm time and snooze time. Use "up" and "down" to set the hour and minute. The repetition time is 1-60 minutes each time, 3 times in total Easy to read: The digital alarm clock has a large LED digital display, you can easily adjust the display brightness according to your personal preferences. 12 and 24 hour time display Adjustable brightness: If you find that the LED light is too bright at night, you can turn it down by pressing the "UP" button, long press the light button to turn off the LED light, or unplug the power cord and run the clock in power saving mode Specification: Material: plastic Power: AAA battery*3 (not included)/USB cable Size: about 16*6cm Package included: 1 x Clock 1 x USB Cable