A signal containing the precise time, day and date, measured by an atomic clock accurate to one second every 100,000 years, is sent directly to the watch using standard radio waves. This signal is picked up overnight by the timepiece which automatically adjust the date and time.


Combined with our proprietary light powered Eco-Drive technology, when owning a Citizen Atomic Timekeeping watch you will get precise time powered by any light source.

With a margin of error of just one second in 100,000 years, CITIZEN’s watches receive radio signals from an atomic clock to set the time correctly.