Measuring Capacity: 24 hours, Measuring Modes: Elapsed time, split time, Measuring Unit: 1/100 second (for the first 60 minutes) 1 second (after 60 minutes) Dual Illuminator: Separate illumination of the analogue and digital components ensures optimum readability in low light conditions., LED light, Selectable illumination duration (1.5 seconds or 3 seconds), With afterglow A full auto-calender displays the day (days of the week can be selected in six languages), date, month, and year (accurate to 2099). You can run the digital display in a 12/24 hour format. The push buttons can be set to have a tone when operated or not. One simple yet useful upgrade Casio made to the GMB2100, is the addition of lume for the hour markers, not just luminous hour and minute hands, as was the case with the GM2100. Both have on-demand dual LEDs for visibility in total darkness, still, the fully-lumed dial is a nice touch.

With the Casio Watches App, you can set the world time with 38 time zones (38 cities + coordinated universal time), city name display, daylight saving on/off, auto summer time (DST) switching, and Home city/World time city swapping (approximately 300 cities in total). With a push of a button, hands are moving and permit a free visibility of functions like stopwatch or date. Even with a mobile Bluetooth connection, the movement is accurate to -/+ 15 seconds per month. The approximate battery operating time is 7 months when fully charged, with normal use, even without light exposure, and 18 months when stored in total darkness and the power save mode activated. While the module is not Bluetooth connected or solar-powered, there’s a certain level of reliability that can be appreciated by a watch you set yourself and that’s powered by replaceable batteries. Not to mention, this allows Casio to offer a solid dial — versus a semi-transparent dial that’s required for sunlight to enter on a solar-powered watch — with the attractive vertical brushed vapor finish. There are almost always trade-offs, and this is a good one considering the dial, to me, is one of the primary highlights of this watch.Daily Alarms: Each will sound every day at the time you set, Hourly time signal: The watch beeps every hour on the hour A luminous coating provides long-term illumination in the dark after only a short exposure to light. 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. Perfect for free diving without scuba gear: the watch is water resistant up to 20 bar according to ISO 22810.

The button tones for using the mode button can be turned off. This means that the watch no longer beeps when switching from one function to another. Preset alarm or countdown timers remain active when the button tones are deactivated. The metal bracelet of the GMB2100 is nicely tapered and feels good on the wrist. Yet what’s practically unavoidable for any watch with an integrated metal bracelet, is the added heft. The bracelet, and to a lesser extent, the heavier module and full-metal case construction, make for a watch that weighs 168.9 grams versus just 71.5 grams for the GM2100 with a resin strap. Titanium, forged, and ceramic are three options to reduce weight from bracelets, however, those also add cost. A fourth option, and one that’s been used by Casio in the past, is to essentially hollow out a steel bracelet and fill it with resin, which significantly reduces weight while not exceedingly raising the cost. Two examples of that within that MT-G collection can be seen here and here. Despite weight savings, some consumers will never want a strap over a metal bracelet, especially for a sports watch. Maybe because of the looks, or perhaps they prefer the heavier feel or both. Nevertheless, Casio offers both, although, for the time being, there’s no way to add a factory metal bracelet to the GM2100 or a factory strap to the GMB2100. Synthetic resin is the ideal material for wrist straps thanks to its extremely durable and flexible properties.The combination of stainless steel and glass fiber reinforced resin supports the stability of the watch and provides a better wearing comfort.