Casio Men's Wave Ceptor watch #WVQ-141DA-7AV Atomic Timekeeping(Receives time calibration radio signals which keep the displayed time accurate,Auto receive function (6 times per day),Manual receive function,Signal: WWVB, Frequency: 60kHz 50M Water Resistant, LED Light with Afterglow, Daily Alarm Auto Calendar (pre-programmed until the year 2099),Accuracy: +/-20 seconds per month (with no signal calibration) Battery CR1620, Approx. battery life: 2 years, Module 4756 Size of case / total weight: 51.0 x 40.0 x 10.5mm / 155g