Our consumer electronics products include radio controlled clocks and watches wireless weather stations power monitors and other measuring devices. We introduced radio controlled clocks to the US market in 1991 and continue to be on the cutting edge of this technology in America. Our weather instruments clocks and watches are calibrated daily to the atomic time standard of the National Institute of Standards and Technology. Atomic Digital Wall Clock Black has an attractive silver finish and displays the most precise and accurate time possible. A radio signal is received daily from Colorado that updates the atomic clock to within one second of official U.S. government time. The atomic clock even automatically res ets for Daylight Savings Time. Wireless outdoor temperature range: 39.8 degrees Fahrenheit to +139.8 degrees Fahrenheit or (39.9 degrees Celsius to 59.9 degrees Celsius). Indoor temperature range: 14.2 degrees Fahrenheit to 99.9 degrees Fahrenheit or (9.9 degrees Celsius to 37.8 degrees Celsius). Transmission range: Up to 200 Feet. Transmission frequency: 915 MHz. Atomic time and date with manual setting. Automatically updates for Daylight Saving Time (on/off option). 12/24 hour time display. Perpetual calendar. Time zone setting. Time alarm with snooze. Wall hanging or free standing. Power Requirements main unit: 2 AA batteries (not included). Power Requirements TX38UIT remote sensor: 2 AAA batteries (not included). Dimensions: 8.95 x 1.2 x 7.1 .