The Sharp Atomic Alarm Clock with Indoor Temperature has a built in receiver that automatically synchronizes itself with the WWVB radio broadcast by the US Government's National Institute of Standards and Technology (NIST) in Fort Collins, Colorado. The Atomic Clock will always be accurate to within one second as it receives daily WWVB updates. The clock may be hung on the wall using the hang hole at the back of the clock or displayed on your nightstand by pulling out the kickstand. You will always know what day it is with a quick glance thanks to the calendar and the day of the week display. You also get the benefit of real time indoor temperature displayed on your clock. It's easy to illuminate the whole display for 5 seconds, just press the snooze button on top of the clock. The backlight will also illuminate when the alarm sounds.