The popular G-Shock GA100-9A watches are made by Casio. G-Shock watches are recharged via solar panels on the surface of the watch, and receive a remote time-calibration signal to keep the time accurate. The G-Shock GA100A-9A alarm can be set in a few easy steps.
Set the alarm time. Press the button at the bottom left of the watch face until you see the alarm indicator.
Set the hour by pressing the top left-hand button when you are in alarm mode. The hour digits will flash when they have been selected. Then press the bottom right-hand button to set the hour. Hold the button down to run quickly through the hours. Once you reach the desired hour, either press the top left-hand button or wait until the hour digits stop flashing. The hour is now set and the alarm is on.
Press the bottom left-hand button again to select the minutes. The minutes digits will begin to flash when they have been selected. Then press the bottom right-hand button to set the minutes. Ensure the alarm is set to a.m. or p.m. as desired.
To set an alarm for a specific date, press the bottom left-hand button to reach the date and then the month. Use the bottom right-hand button to set the month, date hour and minutes.
Stop the alarm from sounding by pressing any of the buttons on the watch. Otherwise the alarm will sound for a total of 20 seconds.