This atomic alarm clock is very accurate by automatically synchronizing to the radio signal emitted from the U.S. Atomic Clock in Colorado. Or you can set the time manually. Time and temperature can be projected on ceiling or walls. They can be rotated 180 degree. With bright orange backlight， it is easy to read time in the dark.Features:Accurately display time with DST by automatically synchronizing to the radio signal emitted from the U.S. Atomic Clock in Colorado.Specially designed projection function， time and temperature can be projected on ceiling or walls， it is fun.The indoor temperature is displayed in °C or °F.It also have regular alarm and snooze function.Time format is optional: 12H or 24H.With bright orange backlight， it is easy to read time in the dark. Note: For users outside USA， the WWVB time can not be received. Please set time manually.Specifications:Color: BlackPowered Supply: 3 * AAA Batteries(not included)Item Size: 17.8 * 3.3 * 10.8cm / 7.0 * 1.3 * 4.25in(L*W*H)Item Weight: 235g / 8.3ozPackage Size: 20 * 4 * 12cm / 7.87 * 1.57 * 4.72inPackage weight: 315g / 11.1ozPackage List:1 * Atomic Clock1 * User Manual