Space-saving (5.6" x 2.9" x 1.9") AC powered, with large white LED numbers easy to read day or night; battery backup saves time during power outage. Please NOTE:It is NOT a battery-powered alarm clock. | Easy snooze with a simple press of anywhere on the top. | Easy-to-use digital alarm clock. Even no need instructions to operate it. | Get your personal comfort brightness with 0-100% dimmer slider, and enjoy a fresh morning with adjustable alarm volume from 30-85db. | Outlet Powered with Battery Backup : Plug in to power the clock with the included DC adapter . 2* AAA batteries ( not included ) needed for storing time and alarm settings in case of power outage. During the backup battery, the screen will go blank and alarm will not sound.