Full-metal versions of G-Shock’s Square and CasiOak models are among the most popular watches in the lineup. The first all-steel G-Shock “Square” was presented at the Baselworld fair in 2018, and an all-steel “CasiOak” had to wait until 2022 to see the light. These premium models are much appreciated and in great demand. After some other colorful variations, Casio is now adding blue to the standard all-steel models by introducing the GMW-B5000D-2 and GM-B2100AD-2A.

Full-metal G-Shock Square models exist in many variations and colors. Full-metal CasiOaks, however, are not as common. So, specifically for the latter, the newly introduced blue version is a welcome addition. Tip: Shockbase offers a complete database of all G-Shock models to date.

G-Shock GMW-B5000D-2 and GM-B2100AD-2A

G-Shock GMW-B5000D-2 and GM-B2100AD-2A

Let’s start with the GM-B2100AD-2A, the all-stainless-steel CasiOak with a blue dial. It’ll be clear that this is the bluest of the two. Including the raised minute track, the entire dial is blue except for the digital window, which, unfortunately, is black. Why “unfortunately”? Well, these small digital displays are already difficult to read in a positive layout; being the negative version doesn’t make it any better. However, from an aesthetic point of view, the choice is understandable.


Module 5691 for the GM-B2100AD-2A

G-Shock provides CasiOak models with several types of movement modules. In 2019, the first models had the battery-powered 5611 module that had to be manually set to the right time. This is still used in the majority of basic CasiOak models. Then, in 2022, Casio presented the updated module 5689, which offers solar charging and a Bluetooth connection to copy the time from a connected smartphone. The connection can also be used to send settings to the watch. For all-steel models, including the new GM-B2100AD-2A, Casio adapted the 5689 module slightly and named it 5691. The module connects to the new Casio Watches smartphone app, available via Apple’s App Store and Google Play. So far, no CasiOaks have had Multi Band 6 time synchronization. But who knows? We might see them in the future.


CasiOak functions

The 5611 and 5689/5691 modules have similar functionality except for solar charging and Bluetooth. Both CasiOak modules offer all the commonly used functions, like timekeeping, world time, a stopwatch, a countdown timer, and alarms. The more modern 5689/5691 modules have way more world cities and probably some additional settings or functionality. I don’t think these extra features will make that much of a difference, but for me, the solar charging would be a huge plus.


Two other differences might also be essential to you, though. First is the way the day is indicated on the dial. The earlier 5611 module, which powers the watch above, shows the day with a little hand in a register at the 9 o’clock position. The newer 5689 modules can show the date abbreviated in the digital window between 4 and 5 o’clock (but not simultaneously with the date). This is less visible and takes longer to read. The other significant difference, at least for Europeans, is how the date is displayed in the small digital display. On the 5611, it’s always MM/DD, while the 5689 and 5691 modules offer the choice between MM/DD and DD/MM. For me, then, both module generations have their (dis)advantages.



Then there’s the new GMW-B5000D-2 with a blue outline around the dial. It isn’t much different from the first all-stainless-steel Square presented in 2018. Technically, and in terms of functions, they’re equal; it’s just that the current 3539 module is upgraded to a new Bluetooth protocol. As mentioned earlier, Casio also introduced the new Casio Watches smartphone app, to which the older module 3459 also connects. Again, the app is available through Apple’s App Store and Google Play. The former app, G-Shock Connect, is being phased out. For users of the G-Shock Connect app, Casio provides auto-data-transfer functionality to the new Casio Watches app so that one doesn’t have to enter watch details manually again.


Negative display

Besides the blue line and updated module, the GMW-B5000D-2 differs in its display from its grandfather, the GMW-B5000D-1. While the first all-steel Square has a positive display, its blue descendant sports a negative one. It has light numerals on a dark background. There might be reasons to use a negative display, but readability isn’t one of them. However, as mentioned above, for the GM-B2100AD-2A, a dark display in combination with a blue dial looks exceptionally good. Also, regarding readability, I think it’s mainly an age thing. It’ll probably only be an issue when one’s eyes become less effective at a later age. However, this article shows that, in general, more Fratello readers choose a positive display over a negative one.


The finish and wearability

Remarkably, the GM-B2100AD-2A and GMW-B5000D-2 feel and wear like watches in a much higher class. “Punching above their weight” isn’t the proper expression here. The weight of both models —166 grams each — is impressive and ensures that wearing is a solid experience. Even the stainless steel bracelets feel comfortable and look the part, which is very different from what we often see in the sub-€1,000 price segment. Using a little spring bar in each link makes them easy to size, and there’s the possibility of fine adjustment in the clasp.


Conclusion and pricing

The GMW-B5000D-2 and GM-B2100AD-2A add a popular color to G-Shock’s all-stainless-steel Square and CasiOak models. The blue dial color is obtained by metallic vapor deposition, which results in a beautiful, vibrant hue. It adds an attractive touch to the stainless steel bezel and bracelet. Without losing their toughness or functionality, these G-Shocks become more stylish eye-catchers than their monochrome ancestors. Although G-Shock Square and CasiOak models with much lower price tags exist, I feel that €549 (including tax) for each is not a lot of money. With these stainless steel models’ solid feel and quality finish, they are undoubtedly worth it. You can find more information about the GM-B2100AD-2A and GMW-B5000D-2 on Casio’s website here and here.

What do you think about these color variations? Do you prefer them, or would you stick to their black-dialed ancestors? As always, let us know in the comments below!

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Watch specifications

CasiOak / Square
GM-B2100AD-2A / GMW-B5000D-2
Blue / Blue outlined
Case Material
Stainless steel
Case Dimensions
44.4mm (diameter) × 49.8mm (length) × 12.8mm (thickness) / 43.2mm × 49.3mm × 13mm
Case Back
Stainless steel, screw-in
Casio module 5691 / 3539
Water Resistance
20 bar (200 meters)
Stainless steel with folding push-button clasp
Timekeeping, full auto calendar until 2099 (month, day, date), world time with 38 (CasiOak) or 39 cities (Square), 24-hour stopwatch, 60-minute countdown timer, five daily alarms, and LED backlight
€549 (including tax)
Special Note(s)
GM-B2100AD-2A: Connects via Bluetooth to a smartphone to automatically adjust the time; solar powered / GMW-B5000D-2: Connects via Bluetooth to a smartphone or radio controlled through Multi Band 6 to automatically adjust the time; solar powered