GREAT CASIO with multiple functions ! - 100M Water Resistant, Altimeter, Barometer, Digital Compass, Thermometer, Low Temperature Resistant (-10C/14F), LED Backlight (Super Illuminator) with Afterglow, World Time 31 time zones (48 cities + coordinated universal time), daylight saving on/off. - 5 Daily Alarms and 1 Snooze Alarm, Countdown Timer, 1/10 second stopwatch, Auto Calendar (pre-programmed until the year 2099), 12/24 Hour Format, Button operation tone on/off, Storage Battery CR2025, Approx. battery life: 3 years. - Quartz Movement - Case Diameter: 54.7mm - Water Resistant To 330 Feet