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Casio 51.2mm X 48.7mm Mens Watch
Ref. GA-2000-3AER
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Stepping up in the same colour and case shape
The GA-2000 sits within a generation of G-Shocks built around Carbon Core Guard, a structure that weaves carbon fibre through the resin case to absorb impact without adding mass. The result is a watch that weighs just 64 grams across a case that runs over 51mm lug to lug — lighter than most dress watches of similar diameter, despite being designed to take punishment. The olive exterior reads as muted and purposeful on the wrist, and the 24mm lug profile is a quiet but meaningful departure from G-Shock convention. It accepts standard aftermarket straps through quick-release levers, with no adapters or tools required — something the broader G-Shock catalogue has rarely offered. At 200m water resistance the watch is genuinely submersible, and at 14.1mm thick it sits closer to the wrist than the case footprint would suggest.
- Reference
- GA-2000-3AER
- Brand
- Casio
- Case size
- 51.2mm
- Case thickness
- 14.1mm
- Lug width
- 24mm
- Case material
- Resin
- Case shape
- Round
- Dial
- Black
- Crystal
- Mineral
- Movement
- Quartz
- Calibre
- 5590
- Functions
- Chronograph, Date, Stopwatch, Countdown timer, Alarm, Backlight, World time, Dual display
- Water resistance
- 200m
- Bracelet / strap
- Rubber strap
- Strap colour
- Green
- Clasp
- Buckle
- Lume
- Luminous
- Retailer
- Goldsmiths
Additional specifications
- Lug-to-lug
- 51.2mm
Learn more about Casio
Tadao Kashio founded Kashio Seisakujo in Tokyo in 1946 as a machine shop. The company's first success was a finger ring that held a cigarette, and its second was the 14-A of 1957 — the world's first all-electric compact calculator, which used solenoids rather than gears.
Casio entered watchmaking in 1974 with the Casiotron, a digital watch with an automatic calendar that knew the varying lengths of months. The company approached watches as an electronics manufacturer rather than a horological one, and that difference produced the G-Shock.
The G-Shock came from a single engineer, Kikuo Ibe, who broke a watch his father had given him and set out to build one that could not break. The specification was three tens: survive a ten-metre drop, ten bars of water pressure, and ten years of battery life. It took over two hundred prototypes, and the solution was suspending the module inside the case on a cushioned internal structure rather than mounting it rigidly. The DW-5000C shipped in 1983.
It became one of the most durable product designs in any category, adopted by militaries, emergency services, and skateboarders alike, and Casio has since added solar charging, radio and GPS timekeeping, Bluetooth, and full-metal and carbon variants.
Casio also produces the Edifice, Pro Trek, and Oceanus lines, and remains an independent Japanese public company.
- 1946
- Tadao Kashio founds the company in Tokyo.
- 1974
- The Casiotron is Casio's first digital watch.
- 1983
- The G-Shock DW-5000C survives Kikuo Ibe's three-tens brief.
- 1994
- The Frogman extends G-Shock to ISO dive certification.
Manufacturer’s guarantee
What the specifications mean
A watch built to be worn hard and got wet.
Strengths
- 200m water resistance, rated for actual diving
- 51.2mm lug-to-lug keeps the 51.2mm case wearable
- Luminous hands and markers for low light
- Second time zone for travelling
Worth knowing
- 51.2mm is a large watch with real presence
- 14.1mm thick, so it will not disappear under a cuff
Compare alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | GA-2000-3AER |  DZ4477 |  PEWJB21953411 |
|---|---|---|---|
| Price | £129 | £139 | £125 |
| Case size | 51.2mm | 51mm | 51mm |
| Water resistance | 200m | 100m | 50m |
| Movement | Quartz | Quartz | Quartz |
| Strap | Rubber strap | Stainless steel bracelet | Leather strap |
| This watch |
|
|
Your new watch
Frequently asked questions, and things you should know about this watch
Can I swim with it?
Yes. At 200m it is rated for swimming, snorkelling and recreational diving.
Will the glass scratch?
It can, over time. Mineral glass handles daily wear but will pick up fine scratches that sapphire would not.
Does it need a battery?
Yes. It is quartz, so expect a battery change every two to three years at a jeweller.
What size strap does it take?
24mm. Any strap of that width will fit, and on most modern watches quick-release bars make the swap a two-minute job with no tools.
Will it fit my wrist?
Lug-to-lug is 51.2mm, which suits wrists from roughly 17.5cm (7 inches) upward.
Lug-to-lug decides fit more than case diameter does.
Is it a men's or women's watch?
Listed as men's.
Cheapest place to buy
Goldsmiths is the only UK retailer we track stocking this reference, so there is nothing to compare it against today.
Who are Goldsmiths?
Goldsmiths has been selling watches in Britain since 1778 and is part of the Watches of Switzerland Group, which is listed on the London Stock Exchange. They are an authorised dealer, so a watch comes with the manufacturer’s own warranty.
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