Bracelet designs

REVIEW: G-Shock GA-B2100 “CasiOak”

In 2022, G-Shock upgraded its original GA-2100 collection – nicknamed “CasiOak” for its octagonal shaped bezel – by adding Bluetooth and solar power.

New G-Shock GA-B2100 “CasiOak” is Casio’s most affordable octagonal bezel watch to receive Bluetooth and solar and comes in four variants, the GAB2100C-9A (yellow), GAB2100-2A (dark blue), GAB2100-3A (dark green), GAB2100-1A (black).

Following the debut of the original GA-2100 series – and the success it achieved – Casio introduced the GM-2100 series which is a high-end metal-clad version of the CasiOak case. Like the original GA-2100, the GM-2100, which we reviewed here, doesn’t include Bluetooth or solar.

As a natural evolution, however, Casio has also recently released an all-new all-metal version of the GM-2100 series, called the G-Shock GM-B2100, with Bluetooth and solar power, in addition to giving it a more sturdy metal build.

G-Shock CasiOak GAB2100-1A Flat Away

The two potential drawbacks of the recently announced CasiOak all-metal GM-B2100 models are the higher price tag of $550+ and the 165-gram weight. Thankfully, compared to the $99 resin watch (the original GA-2100 series), the new resin-carbon case (GA-B2100 series) has gone down to just $150, and while you only get not a premium metal-clad case, metal bezel or metal bracelet – you get Bluetooth and solar power, ensuring your watch is always powered and set at exactly the right time, with little to no fuss. necessary interaction. Just pick it up and you’re good to go, as long as it sees light occasionally to charge the battery.

G-Shock CasiOak GAB2100-1A

Importantly, the addition of Bluetooth and solar power, added no weight or size to the watch, meaning the GA-B2100, has the same case dimensions of 45.4mm diameter x 11.8mm resin case (48.5mm lug to lug) and still weighs 51 grams, just like the original GA-2100.

G-Shock CasiOak GAB2100-1A Wrist Kick

On the wrist, the GA-B2100 watch, which uses the same resin strap with steel pin buckle and buckle closure as its predecessor, wears exactly the same as the GA-2100. Of the three most iconic G-Shock collections – the 6900 Series, 5000 Series and 2100 Series – this is perhaps the most comfortable.

G-Shock CasiOak GAB2100-1A Wrist Kick

Plus, the collection’s continued sales popularity suggests this case style might be the most desirable look in the full breadth of the G-Shock brand. Personally, this is one of my favorite styles because it’s both so pretty and super comfortable on my wrist.

G-Shock GA-B2100

Construction wise, the watch is mostly resin, with carbon resin used on the inner case to reduce shock (Carbon Core Guard Structure), which is only visible on the back of the watch . The dial is protected by mineral glass, which isn’t quite as nice as sapphire crystal, but considering the price, that’s to be expected. Also, the glass is protected by design, as it sits below the plane of the bezel (shielded). The caseback is made of stamped steel and is secured with four screws, as opposed to a screw-down design, which, again, is a result of targeting a low price. Even with some of the required cost-cutting measures, you still get G-Shock’s impressive 200-meter water resistance.

G-Shock CasiOak GAB2100-1A flat side

Functionally, the GA-B2100 comes with the usual plethora of features, while keeping the dial relatively minimalist, which is better for me as too much takes away from readability and usability.

G-Shock GA-B2100

There is a sophisticated universal time function with 38 time zones (38 cities + Coordinated Universal Time), city code display, city name display, daylight saving time on/off, automatic daylight saving time (DST) switching , Home City/World Time City switching. A countdown allows you to measure as accurately as one second and count up to 60 minutes. The full automatic calendar is accurate up to the year 2099. There is a hand change function (the hands move apart to provide an unobstructed view of the contents of the digital display). A stopwatch offers the ability to track elapsed time (including lap/split times) up to 24 hours, with an accuracy of 1/100th of a second.

Close-up of the G-Shock CasiOak GAB2100-1A dial

Additional functions include 12/24 hour time format selection, date/month display swap, day display (weekdays selectable in six languages), 5 daily alarms, hourly top, bOn/off utton working tone and battery level indicator.

G-Shock GA-B2100

When connected to the Casio Watches app via Bluetooth, the GA-B2100 can perform automatic time adjustments for extremely precise timekeeping, easy watch setting with access to an expanded number of global cities (approx. 300), time and location data, reminders and a phone finder feature that helps you find your phone by activating it on the watch. Even without a Bluetooth connection, regular timekeeping is displayed via the analog hour and minute hands (the hand moves every 20 seconds), with an accuracy of ±15 seconds per month (without mobile link function). When the watch is connected to Bluetooth, it is as accurate as a cell phone. The battery level, as well as the modes, are indicated in the sub-dial located at 9 o’clock. In the digital display on the lower right quadrant of the dial, a digital display reads the hour, minute, second, PM, month, date and day.

G-Shock CasiOak GAB2100-1A light and LED

Every G-Shock is highly impact resistant, and this is no different. To see in dark environments, Casio has added a generous amount of light, but only to the hour and minute hands, which somewhat reduces utility compared to adding light to the hour markers. In addition to the lume, there’s also a push-button dual-LED illuminator which greatly improves nighttime readability (and can be set to illuminate for 1.5 or 3 seconds), although I found the downlight extremely difficult to press due to its size and position.

G-Shock CasiOak GAB2100-1A light

To save power, the watch display will automatically turn off to save power when the watch is left in the dark. Approximate battery operating time is 7 months on a fully charged battery (with normal use without exposure to light after charging) 18 months on a fully charged battery (operating period when stored in the total darkness with the energy saving function activated after a full charge).

G-Shock CasiOak GAB2100-1A Wrist Kick


Casio listened to its core audience and improved on the original CasiOak, giving it Bluetooth and solar, which are called out in bright yellow and blue font on the dial at 3 o’clock. With these additions.

The new dial features a translucent surface, which is needed to let light through to power the battery. With this change, Casio has chosen to give the dial a new sunburst treatment, which not only adds solar energy, but also elevates the dial visually over the original CasiOak.

Having Neobrite on the hour and minute hands is awesome, and that exclusive lume seems to be on par with the luminosity of the lume seen in the industry, however, it would have been great to see the lume also applied to the indices or at least just above the indexes on the outer circle of the chapters. The LED illuminator, at least in part, compensates for this omission, although the LED eats battery, only stays on for up to 3 seconds, and requires pressing a button which isn’t as easy to activate as the push buttons found on models like the 6900 series, which places a large button just below the dial at 6 o’clock.

For those who want a CasiOak and are adamant about having Casio’s desirable Bluetooth and Tough Solar technology, this should be of interest. And for those who want the same technology, but housed in a metal-clad CasiOak, that’s also now an option, albeit at a higher price. You won’t find any other watch with the durability and technology of the GA-B2100, for close to the price of this watch, making it a bargain.

The G-Shock “CasiOak” (Ref. GA-B2100-1A) is available now from authorized G-Shock retailers, G-Shock SoHo and for $150.

Learn more about G-Shock.

G-Shock GA-B2100