MainStays Atomic Digital Wall Clock with Built In Temp /Calender. Condition is "New" 7.8 in W x 1.1 in D x 5.47 in H (19

8 cm x 2.8 cm x 13.9 cm)

Automatically adjusts for daylight savings time.

Perpetual Calendar

Indoor temperature

How does an Atomic Clock Work?

 from nist dot gov

Some manufacturers refer to their radio controlled clocks as "atomic clocks", which isn't really true. An atomic clock has an atomic oscillator inside (such as a cesium or rubidium oscillator). A radio controlled clock has a radio inside, which receives a signal that comes from a place where an atomic clock is located.

In the United States, the signals received by radio controlled clocks originate from NIST Radio Station WWVB, which is located near Fort Collins, Colorado. WWVB broadcasts on a frequency of 60 kHz. Your radio controlled clock actually has a miniature radio receiver inside, which is permanently tuned to receive the 60 kHz signal.