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Casio 2100 Series 49.3mm X 44.4mm Mens Watch Blue
Ref. GBM-2100A-2BER
Sits in Casio’s upper tier here — more premium than three quarters of the Casio watches we list, which start at £25.
Price range £25 to £919 across 70 Casio watches in stock.The GBM-2100 belongs to the "CasiOak" lineage — the octagonal G-Shock format that acquired its nickname through the obvious visual debt it carries — and this model updates that template by pairing solar charging with Bluetooth, removing the two most common reasons to interact with the watch at all: battery replacement and manual time correction. At 11.9mm thick, it wears substantially flatter than most G-Shocks rated to 200 metres, which is unusual for a watch built to that standard. The 72-gram weight is equally improbable for a case finished in stainless steel; the answer is the bio-based resin core beneath it, which carries the structural load while the steel bezel — worked to a circular hairline — handles the appearance. The blue dial gets its depth from a vapour deposition process rather than paint, giving it a metallic quality that shifts under different light.
- Reference
- GBM-2100A-2BER
- Brand
- Casio
- Collection
- G-SHOCKCase Size: 44
- Case size
- 49.3mm
- Case thickness
- 11.9mm
- Case material
- Stainless steel
- Case shape
- Octagonal
- Dial
- Blue
- Crystal
- Mineral
- Movement
- Solar
- Functions
- Stopwatch, Countdown timer, Alarm, Backlight, World time, Solar powered, Bluetooth, Dual display, Digital display
- Water resistance
- 200m
- Bracelet / strap
- Rubber strap
- Strap colour
- Black
- Clasp
- Buckle
- Lume
- Luminous
- Retailer
- Goldsmiths
Additional specifications
- Lug-to-lug
- 49.3mm
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.
This watch appears in Stainless Steel (2,298), 44mm and Over (732), Blue Dials (615), Sports Watches (563), Dive Watches (379) and Solar & Kinetic (103).
Manufacturer’s guarantee
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?
No. It charges from light, and the cell behind that is designed to last a decade or more.
Will it fit my wrist?
Lug-to-lug is 49.3mm, which suits wrists from roughly 16.5cm (6½ 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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