Atomic Timekeeping
The atomic timing signal is accurate to 1 second over 20 million years.
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Atomic Timekeeping watches are synchronized to an atomic clock for superior accuracy. With a margin of error of just one second in 100,000 years, Citizen A·T watches receive radio signals from an atomic clock to set the time correctly. The current geographical areas in range of atomic clocks include Japan, China, North America and Europe.