Even amongst non-watch enthusiasts, G-SHOCK is a bonafide household name, responsible for producing some of the most recognizable and iconic digital watches in recent history. Paying tribute to the original G-SHOCK model from 1983 — the DW-5000C — the company introduced a modern homage to its inaugural timepiece in 2019 with its GA-2100 Series. Borrowing aesthetic elements from G-SHOCK’s DW-5000C watch with its octagonal bezel and dimpled band, the GA-2100 Series also just happened to sport an unmistakable resemblance to another incredibly iconic watch, the Audemars Piguet Royal Oak — a visual link that’s earned the GA-2100 Series the unofficial monicker of the “CasiOak.” As a more than $500 G-SHOCK, it can be difficult to know exactly what to make of the CasiOak. Wanting to find out for ourselves, we’ve gotten a hold of one of the new all-metal versions of G-SHOCK’s GA-2100 watch — the  GMB-2100D-1A —  to put it to the test in this hands-on review. 

Whether you view it as a novel design or a blatantly Royal Oak-inspired item, the all-metal GA-2100 is simply a stunning watch. Despite boasting the exact same design as the resin construction version, the use of an all-alloy construction for this version of the watch’s case and band results in a product with a markedly more premium feel. This use of a more premium construction has also been further elevated through the all-metal G-SHOCK’s surprisingly top-shelf fit and finish, with beautifully-polished surfaces adorning every visible face of the timepiece. In typical G-SHOCK fashion, the GA-2100 Series is far more than a mere looker, too, with the watch retaining the ultra-high levels of durability and immense utility that G-SHOCK’s watches have become famous for — though we’ll touch more on this laundry list of features below. The standard suite of G-SHOCK functionality has also been supplemented via soar charging and Bluetooth/smartphone connectivity. 

The G-SHOCK GA-2100 is constructed around a 44.4mm case all-stainless steel case that clocks in at just 5.8oz — with the metal bracelet included. Benefitting from the use of G-SHOCK’s proven Slimline module, the entire watch manages to cram its enormous slew of functions into a housing measuring just 12.8mm thick. An octagonal bezel and metal pusher buttons further complement the all-alloy case, as does the watch’s screw-lock-secured back plate. And, while the case might not be composed of G-SHOCK”s signature impact-absorbing resin, the stainless steel case’s internals have been fortified via the Casio sub-brand’s layered fine resin shields setup and high-density mounting, affording the GA-2100 robust impact and shock resistance, as well as a water resistance rating of 200 meters (or 660’). With the exception of its embossed bezel, the entire watch has also been treated to a mirror-polished finish that’s shockingly uniform. 

Sporting an analog, digital hybrid configuration, the GMB-2100D-1A’s dial is comprised of a dual-layer item with a subtle sunray texture that benefits from the use of both additive manufacturing and microfabrication. Featuring sword-style hour and minute hands paired with a battery level indicator at 9 o’clock that occupies its own sub-dial with a circular-brushed finish. Between 3 and 6 o’clock, the dial also boasts a pair of digital readouts. Sitting under a scratch-resistant mineral glass lens, the dial also benefits from the use of both Neobrite and a double-LED backlighting unit. The dial also features Casio’s Hand-Shift feature — which moves the analog hands out of the way of the digital display for it to be more easily read. The use of raised, lume-capped, vertically-brushed rectangular indices give the watch a more traditional flavor, while still being instantly recognizable as a G-SHOCK dial. Best of all- the entire dial conceals a solar array that keeps the watch charged for months — if not years—  at a time. 

At the heart of the GMB-2100D-1A is a Japanese-made solar-powered quartz movement known as the G-SHOCK Tough Solar unit. Largely maintaience free and armed with up to 18 months of battery life on a single charge, this quartz movement is accurate to : ±15 seconds per month — blowing most automatic and mechanical movements out of the water. On top of 5 built-in daily alarms, a full auto calendar, and a countdown timer, the watch also sports Bluetooth connectivity and the ability to pair with G-SHOCK’s dedicated app that includes features such as a database of 300 world time cities, auto time adjustment, a phone finder, and a reminder function. This app also includes the ability to simple tap a button on the watch and have the timepiece automatically record the user’s exact date, time, and GPS position on a map. This amalgamation of utility, ample functionality, and highly-accurate timekeeping collectively make for one very impressive quartz movement. 

In addition to seeing the OG CasiOaks’s resin case construction jettisoned in favor of an alloy item, the G-SHOCK’s signature resin band has also been recreated in metal. This stainless steel bracelet replaces the normal G-SHOCK resin strap’s single-unit construction for a series of Y-shaped links that retain the Japanese brand’s trademark dimples. This solid stainless steel bracelet also sports a one-touch 3-fold clasp and an all-vertically-brushed finish — a motif that contrasts the case’s all-polished finish and match’s the brushing on the bezel. Also equipped with four micro-adjustment points — an element typically reserved for more premium, high-dollar watches — the bracelet does sport the same immense level of comfort offered buy G-SHOCK’s resin bands. 

 While the GMB-2100D-1A does represent venturing into novel territory for the brand in many ways, this all-alloy GA-2100 Series is objectively a G-SHOCK through and through. From the watchmaker’s signature levels of durability to its typical wealth of features and functionality, the GMB-2100D-1A retains these hallmark traits — and does so in spades. With that said, the GMB-2100D-1A is an unmistakably more premium offering through and through. So, while it may share a familiar octagonal case and bezel shape, the CasiOak is far more than a cheap imitation of a grail watch, standing as the next evolutionary step in G-SHOCK’s 40-year history.