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[G-Shock Review] GA-2100-4A — the Red World for Creative People

The thinnest GA-2100 series in shock-resistant direction G-SHOCK is rapidly gaining popularity around the world. Honestly, I have already begun to doubt the possibility of repetition of the success of the GA-100/110, but it turns out that the Japanese can still surprise and create products of universal enthusiasm. Despite having a review of the black model GA-2100-1A, I decided to consider the red version of the GA-2100-4A. Still, before us, perhaps, is a future legend, which means that you can study different color options of the popular case on the blog.

GA-2100-1A1, GA-2100-4A, GA-2100-1A

At the moment, the GA-2100 series is represented by 3 colors: red, black and black.

Only blacks can be completely black or with white accents [on time stamps and hands]. A model with white accents is definitely responsible for good readability of information: GA-2100-1A [and already GA-2100TH-1A]. Others decided to completely “merge” into one color, which undoubtedly has its own highlight. This is exactly what we’ll talk about in the review, since the red GA-2100-4A are just like that …

Red color. Agree, you do not always see a person with a red watch. This is the fundamental difference between the representatives of G-Shock from another watch world. Being vibrant and at the same time staying true to your filisofia is a key feature of the brand. Many people like to criticize Casio for such an abundance of color variations in the style of “it would be better to come up with a new series, but not play with paints,” but the color variety allowed the company to find a new, creative audience.

Indeed, it is art that allows people to express themselves, and creative individuals especially want something else, not like everyone else. The G-Shock brand groped for this pain point and gave the user a choice. Blue, red, yellow, orange, retro and many other colors can be seen in the news of 2019. Thanks to this choice, creative people have found their watch model, and, believe me, they do not always think about readability, functions, and even more so about technology. The clock should show the time, but at the same time it should still correspond to the state of mind. And that’s all. Fortunately, G-Shock-s can show this condition.

So, return back to today’s hero called GA-2100-4A. The model in this case is created for self-expression. Such a bright red color is impossible not to notice. Well, the watch is very unique, so while you definitely can’t find such on the street. I am sure that creative individuals will definitely appreciate this brightness and find application for it [for the style of clothing or type of activity].

As for the readability of information, not everything is so good here [in general, it’s logical and understandable, because for this kind you do not pay with a wallet, but with some minuses in practicality]. I am writing a review in the evening under normal apartment lighting and I can say the following: electronic indexes are almost invisible at a quick glance, analog time is 90%. Still, in the arrows there are white lines with a non-shaving coating and they save.

I want to separately note the presence of neobrit, since this coating is very sensitive to minimal light rays and perfectly reflects even when its own backlight is triggered, which, of course, is present in the GA-2100-4A. The fact that the hour markers are also red could not but affect the readability: you will focus more on the location of the hands and imaginary indices than on the existing ones [I repeat, in low light]. In the daytime, everything is fine even with electronic data.

Almost always when I review a watch with an inversion type of electronic window [when the background is dark and the values ​​themselves are light], I always declare poor readability. But in such displays there is one huge plus – the backlight.

The backlight that draws all the flaws of the inversion. The GA-2100-4A is no exception. If the lighting is not very good, activate the backlight and the electronic values will be visible even to “your neighbor”. I can not help but pay attention to the red background of the backlight itself, which is also another plus to the general red abundance. Unfortunately, a separate LED does not greatly affect the arrows, but it is possible to consider it. It’s a pity that there is no automatic activation of the backlight depending on the viewing angle, but such automation would not have liked the battery.

Thinness. They write a lot about this, because many people associate G-Shock watches with large “washers” and have every right to do so. Personally, I always ignored coarseness, because thinner models were always present. The GA-2100 series is indeed the thinnest among the G-Shock [11.8 mm], but when I saw the model live, I did not receive a STRONG surprise.

Yes, subtle, but this is not the subtlety that surprises. I would even call the watch just with the usual NORMAL thickness. Compared with the GW-B5600 and I will not say that they stand out by the thickness of the case. In any case, subtlety is good.

The watch sits perfectly on the wrist, because the back cover does not stick out at all, but goes on the same level with the case [which cannot be said about the GW-B5600].

The glass in the watch is mineral. You won’t get another for such a price. Often we see discussions in the comments, they say, glass is on a level with a bezel – NO. The bezel is slightly higher and confidently fulfills its protective function.

The features of the case were well described in the first review.

The inside of the case is a polyurethane layer with carbon reinforcement. The manufacturer calls his creation the Carbon Core Guard structure, which not only improves the impact-resistant properties of the case [carbon is a very durable material], but also reduces the weight of the watch, and this is also important. True, in the case of the GA-2100, the carbon elements are completely hidden inside the watch, and you will not admire them visually [unlike the GA-2000 or GST-B200].

Pay attention to the dark “layer” – this is the carbon part.

Detachable strap. I am not so happy with the possibility of a removable strap, as the assumption that the manufacturer will still be selling more original straps for specific series.

We often faced the lack of original straps on sale for many models and had to come up with a bicycle to solve a seemingly simple problem.

Another no less interesting detail is the shape of the case, which is now not round or even square, but octagonal. The number eight in this case is very arbitrary, because the dial still remained round, but the very idea of ​​the designers is respected. The octagonal bezel, which is responsible for the octagonal look, takes all the attention. By the way, the DW-5000C [the very first G-Shock] had a similar format, and this model was the starting point not only for all subsequent “square” series, but also for the GA-2100 itself. Thus, in one building the glorious G-Shock past and modern durable materials coexist.

“Specifications of GA-2100”]

  • Case / bezel material: Carbon / Resin 
  • Resin Band
  • Shock Resistant
  • Mineral Glass
  • 200-meter water resistance
  • Double LED light
    LED light for the face (Super illuminator, selectable illumination duration (1.5 seconds or 3 seconds), afterglow)
    LED backlight for the digital display (Super illuminator, selectable illumination duration (1.5 seconds or 3 seconds), afterglow)
  • World time
    31 time zones (48 cities + coordinated universal time), daylight saving on/off, Home city/World time city swapping
  • 1/100-second stopwatch
    Measuring capacity:
    00’00”00~59’59”99 (for the first 60 minutes)
    1:00’00”~23:59’59” (after 60 minutes)
    Measuring unit:
    1/100 second (for the first 60 minutes)
    1 second (after 60 minutes)
    Measuring modes: Elapsed time, split time, 1st-2nd place times
  • Countdown timer
    Measuring unit: 1 second
    Countdown range: 24 hours
    Countdown start time setting range: 1 second to 24 hours (1-second increments, 1-minute increments and 1-hour increments)
  • 5 daily alarms
  • Hourly time signal
  • Hand shift feature
  • Full auto-calendar (to year 2099)
  • 12/24-hour format
  • Button operation tone on/off
  • Regular timekeeping
    Analog: 2 hands (hour, minute (hand moves every 20 seconds)), 1 dial (day)
    Digital: Hour, minute, second, pm, month, date
  • Accuracy: ±15 seconds per month
  • Approx. battery life: 3 years on SR726W × 2 Size of case : 48.5×45.4×11.8mm
  • Total weight : 51g

The functional part is very typical: world time [time in another time zone], stopwatch, timer, 5 alarms, the ability to remove the arrows to the neutral position HAND SHIFT, calendar. The window of the day of the week at the 9 o’clock position got an unusual look. These functions are quite enough to enjoy the watch.


For a relatively inexpensive price, you get a creation that is completely unique in style, which is also waterproof, shockproof, thin, light, accurate and functional. If the readability of information is important for you, then just take the model with white hour markers, because the red ones have problems with this. I am sure that the GA-2100 will receive even more color options in the near future, because most likely we are still facing a new democratic legend and a hit in sales in 2020.

Read Quick News on GA-2100:

All News on GA-2100 →

Firstly published, but we carefully translated into English.

Some FAQ moments about G-Shock GA-2100 Series

What is 200 Water resistance?

G-Shock GA-2100 is suitable for professional marine activity and serious surface water sports, but not suitable for diving.

GA-2100 Profile / Casio G-Shock
Average Amazon Price: $100 (yes, we may earn a commission on qualifying purchases from our links to Amazon). Check the Price on Amazon →
Year of first release: 2019
Lineup: STANDART ANA-DIGI (This Line includes Digital and Analog displays on G-Shocks that are the best in “price/quality” category. Usually have traditional digital functions, but with beautiful hands. Don’t worry, the hands won’t prevent you from seeing digits, since there is a special Hand Shift technology that moves them to the neutral position) All G-Shock Standart Ana-digi Watches →
Best for: Small Wrists, Teenagers, Office and Formal Wear, Top in G-Shock Lookbooks
The most distinctive specs:
200-meter water resistance (good for swimming but not for deep diving)
Carbon Core Guard structure (protects the module by enclosing it in a carbon case. The case is made of fine resin embedded with carbon fibers for outstanding strength and crack resistance)
Other colors and full specs: GA-2100 Wiki Page
Only Limited Editions: GA-2100 Limited Editions

G-Shock GA-2100 Rating System

Battery Years★★★
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Muhammad Fairuz bin Haji
Muhammad Fairuz bin Haji
1 year ago

Hyee ..the name is Fairuz (phy-rooz) from Maaysia and i got the watch of my lifetime ..G Shock GA 2100 4A and i love it so much that i wear it 19 hours daily ..damn …i really really love this Redout CasiOak ..

Last edited 1 year ago by Muhammad Fairuz bin Haji
1 year ago


I am new to G Shock. What baffles me about this model is the back case.

The one with you doesn’t seem to have the serial code (or whatever the numbers and letter are) compared to the one in the video.

I am referring to somekind of code imprinted after the text ST STEEL BACK.

I have seen one with it, and one without it. And both appears to be original and not fake.

May I know why?