Smartphone Link uses Bluetooth and G-Shock app for an automatic two-way time sync. Solar powered - self charging design. Full auto LED light with afterglow. World time: 39 time zones (39 cities + coordinated universal time). 1/100 Second stopwatch. Low battery alert and Power saving mode. Full auto calendar. Button operation tone on/off. Date display (day/month). Regular timekeeping with hour minute and seconds. Accuracy: +/- 15 seconds per month. Shock resistant. Water resistant to 200 M. Case size: 49.3 x 43.2 x 13mm.