CASIO watch G-SHOCK Bluetooth Low Energy (Limited Edition) GB-6900AA-5JF Men&rsquo;S Watch Bluetooth Low Energy support Impact-resistant structure World Time 35 time zones (100 cities + UTC), city code display, daylight saving on/off Approx. battery life: 2 years (assuming BLE communication function is used up to 12 hours per day) Full Auto Calendar (pre-programmed until the year 2099)