How do atomic clocks/watches work?
The government owns and operates an "atomic clock" which is located in Colorado. This atomic clock keeps precise time by dropping atoms. It is the most accurate clock in the world and is considered the official US time. The clock is hooked up to a huge radio antenna which sends out a strong radio signal across the entire contiguous US. Our clocks tune into that radio frequency, decode the signal, and automatically set their time to the US atomic clock. The clocks automatically search for the signal at least once a day in order to keep precise time. For more information and a coverage map please go here: National Institute of Standards and Technology

• World Time
• Electro-Luminescent
• Backlight with Afterglow
• 50 Meter Water Resistant
• Atomic Watch
• Receives time calibration radio signals which keep the displayed time accurate
• Time calibration signal reception
• Auto receive function (one time per day at 1:00am)
• Manual receive function
• 25 time zones
• Daylight savings time on/off
• Date alert
• Display flashes when set date is reached
• 1/100 second watch
• Measuring capacity: 99:59'59.99
• Measuring modes: elapsed time, split/lap time, 1st-2nd place
• Daily alarm
• Hourly time signal
• Auto-calendar (pre-programmed to year 2096)
• Low battery warning
• Accuracy: ±20 seconds per month (with no signal calibration)
• Approx. battery life: 1.5 years on CR1620