Auto setting alarm clock with full range dimmer: 4.3 Inches large LCD screen displays eye easy catch blue digit, time and content are easy to read at a glance. 0%-100% adjustable dimmer enable you to set the brightness of display to a comfortable level at will. Advance autoset time: The clock will sets itself to the correct time once plug in, hassle free to set time. Cell button battery included as backup battery, which will store the time, date and alarm setting during main power outage, however it will not support the time display nor trigger the alarm.