When the lights are off, this clock uses laser technology to dynamically project thousands of relaxing stars and the moon, right on your ceiling! It allows you to peacefully drift asleep under a starry, starry sky, in the comfort of your own home. . . .Then when it’s time to get back to reality, simply roll over, press the button and the time will be clearly projected on your ceiling. Measures: 10cm 2 x 7cm H. Takes 3 x AAA batteries (not incl).