180 Adjustable Projector and 4 Level Projection BrightnessProjection alarm clock for bedroom projects ultra-clear time onto wall or ceiling within the optimum projection distance 1.6-9.8ft(0.5-3m). No need to turn your head to check the time. FM Radio and Sleep TimerThis digital alarm clock is more than an alarm clock but also a FM radio, it can store up to 40 favorite radios from 76.0 to 108.0MHz. The sleep timer allows you to fall asleep with the radio within 5-90 minutes and turn off after the specified time you set. USB Charging PortFor this dual alarm clock, there is a slow charge USB port - very good for phone battery. NOT battery poweredThe built-in button battery works for memorizing the time and alarm settings in the case of the main power outage. During the power outage, the screen will go blank and the alarm will not sound, but the clock will display the correct time once power returns. Note: The alarm clock is powered by mains only, not battery powered.