G-Shock GA100-1A1 Watch - G-Shock GA100-1A1 Series watch by Casio. Shock resistant. Magnetic resistant. 200M water resistant. Auto EL backlight with afterglow. Flash alert. World time. 29 times zones (48 cities). Four multi-function alarms and one snooze alarm. Hourly time signal. Auto Calendar (pre-programmed until the year 2099). 12/24 hour formats. Accuracy: +/- 15 seconds per month. Imported.