Tokyo-based Casio Computer Co., Ltd., produces Casio solar watches. Casio solar watches are rugged outdoor watches often marketed as survivalist sportswear. The solar watch uses tiny solar panels embedded in the watch face that converts sunlight into energy. These timepieces store the energy and can power the watch in low-light conditions, if not total darkness, for months. The solar watch can also be equipped with Casio’s “atomic” technology, which allows the watch to capture low-frequency radio transmissions from time stations to provide accurate times.

Expose the Casio solar to bright light or the sun to charge the batteries before setting the time. Ensure the batteries hold a charge strong enough to set the time. Acquaint yourself with the timekeeping mode of the watch. Note the four function buttons located at 2, 4, 8 and 10 o’clock at the edge of the case. A dial illumination button is located at 6 o’clock, according to Casio.com.

Press the 8 o’clock button to set the modes for the various functions: alarm, countdown timer, stopwatch and hand-setting modes. The 10 o'clock button sets other modes.

Hold down the 10 o’clock button of the Casio solar watch to select the mode for the home city digital display to the nearest major city where you live. Hold down the button until the LED displays “USA.” Press the 4 o’clock button to display eastern cities. Press the button at 2 o’clock for western cities. Continue pressing the 2 o’clock button to select the nearest major city. For example, set the display for “LAX” for Los Angeles if you live in a California city. Press the 10 o’clock button again to exit. The Los Angeles time is automatically set.

Press the 8 o’clock button once for the timekeeping mode to manually set the time. Hold down the button at 10 o’clock to set the 12- or 24-hour display. Return to the 8 o’clock button and press it to set the seconds, hour, minutes, year, month and day. These modes appear one after another and each can be set with one push of the 8 o’clock button.

Set the alarm mode by pressing the 8 o’clock button, and then pushing the 4 o’clock button until the alarm screen is flashing. “AL1” will appear. Hold down the button at 10 o’clock and it will flash the hour and minutes. Pushing the 4 o’clock button advances the hours and minutes and pressing the 2 o’clock button reverses the time. Exit the mode by pressing the 10 o'clock button.

Push the 6 o’clock button until “00:00” illuminates in the LED display. Push the button at 4 o’clock to begin the elapsed time. Press it again to stop the stopwatch. Push the 2 o’clock position to clear the timer.