Casio GW5600J-1 G-Shock Atomic Solar Digital Watch This Casio GW5600J-1 features solar power, atomic timekeeping and is water resistant to 200 meters. Atomic watches work by using an internal antenna that receives data such as time, date and other information from the atomic Transmitter in Colorado. This data is transmitted each second for one minute, and does this several times each day for ultra-precision operation. The atomic Solar watch is an amazing feat of technology and environmental awareness that comes from 20 years of evolving G-Shock technology. The tiny solar panel inside powers a battery that you don’t have to worry about changing. It works in low light, and can store a charge for up to 2 years. Features: Atomic Timekeeping Tough Solar Power Shock Resistant 200M Water Resistant Auto EL Backlight with Afterglow World time (30 cities) 4 Daily Alarms / 1 Snooze Alarm Countdown Timer Stopwatch Hourly Time Signal Battery Power Indicator Power Saving Mode Auto