Invisible solar cells in the watch convert light into energy and supply all functions. A rechargeable battery provides the necessary capacity for operation in poor light conditions. On a full charge, the watch can operate for about seven months with normal use without further exposure to light, or up to eighteen months when stored in darkness with power-saving enabled. Regularly exposing the watch to bright light will provide maintenance-free operation for many years. We suggest keeping Tough Solar watches charged up as much as possible and not letting them go to low often, for the health and longevity of the rechargeable battery. The Bluetooth link provides enhanced features through the Casio smartphone app, such as automatic time adjustment (4 times a day), easy watch setting, approximately 300 world time cities, a time & place memory log function, a reminder function, and the phone finder function. (The watch can also be adjusted and operated without using Bluetooth at all.) One notable difference from the GA-2100 is that the subdial indicator on the GA-B2100 shows the function modes and battery level rather than the day of week. The day of week can be displayed on the LCD display along with the seconds. (The LCD display can also display the date with seconds or the hours and minutes with seconds.) For fans of precision: the countdown timers help you to remember specific or recurring events by giving off an audible signal at a preset time. They The time can be set to the nearest second and up to 24 hours in advance.

months on rechargeable battery (operation period when stored in total darkness with the power save function on after full charge)

Comparing Products

Green with inverted LCD display, based on the color scheme of DW-5600B-3V from 1987. Japan model is GA-B2100-3AJF (22,000 yen). months on rechargeable battery (operation period with normal use without exposure to light after charge) Built in Phone Finder - Make your phone emit a loud ring even when it’s on silent with the press of a button

Measuring Capacity: 24 hours, Measuring Modes: Elapsed time, lap time, split time, Measuring Unit: 1/100 second (for the first 60 minutes) 1 second (after 60 minutes) Elapsed time, split time and final time are measured with 1/100-sec accuracy. The watch can measure times of up to 24 hours. Technical amendments and errors excepted. The sizes in figures do not correspond to the original sizes. time zones (38 cities + coordinated universal time), city code display, city name display, daylight saving on/off, auto summer time (DST) switching, Home city/World time city swappingAlternatives: The deluxe GM-B2100 is a full metal version. The more affordable GA-2100 offers the same style but without solar power and Bluetooth.