Project the world's most accurate time on your wall or ceiling in large, easy-to-see numbers! Know the time to one-millionth of a second the instant you open your eyes! This clock accepts signals from the atomic clock in Fort Collins, Colorado for unparalleled accuracy - it automatically calibrates itself daily & changes for daylight saving time too. Also features indoor temperature, day/date display, 12/24 hour time formats, alarm with snooze, blue backlit display, four time zone settings, adjustable projection arm & more. Approx. 6 x 3-3/4 x 1-1/4. Three AA batteries not included. AC adapter included.