
Tap the image to enlarge

Casio All Black Metal Cover Series
Ref. GM-2100BB-1AER
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 132 Casio watches in stock.Part of Casio's G-Shock Metal Covered series, this 44.4mm watch pairs a resin inner case with a black ion-plated stainless steel bezel, keeping the overall profile at 11.8mm deep and the weight at 72 grams. The toughened mineral crystal sits over an analog-digital hybrid dial, where the hands carry a Neobrite luminous coating and shift clear on command to reveal the digital display beneath. The black resin strap fastens with a traditional buckle. Water resistance is rated to 200 metres, and functions include five daily alarms, a 1/100-second stopwatch, a 24-hour countdown timer, and world time across 48 cities.
- Reference
- GM-2100BB-1AER
- Brand
- Casio
- Collection
- G-Shock
- Case size
- 44mm
- Case material
- Resin
- Case shape
- Octagonal
- Dial
- Black
- Crystal
- Mineral
- Movement
- Quartz
- Functions
- Chronograph
- Water resistance
- 200m
- Bracelet / strap
- Rubber strap
- Strap colour
- Black
- Clasp
- Buckle
- Lume
- Luminous
- Retailer
- Goldsmiths
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.
Also in 7 collections
This watch appears in the Casio G-Shock range (85), Chronograph Watches (1,064), Watches 44mm and Over (735), Sports Watches (700), Dive Watches (503), All Black Watches (286) and Dive Watches Under £300 (91).
Manufacturer’s guarantee
Best of 2 retailers
What the specifications mean
A watch built to be worn hard and got wet.
Strengths
- 200m water resistance, rated for actual diving
- Luminous hands and markers for low light
- One of Casio's more premium watches
Worth knowing
- 44mm sits at the larger end
Casio All Black Metal Cover alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | GM-2100BB-1AER | R8873640008 | MK8580 |
|---|---|---|---|
| Price | £199 | £199 | £189 |
| Case size | 44mm | 44mm | 44mm |
| Water resistance | 200m | 100m | 100m |
| Movement | Quartz | Quartz | Quartz |
| Strap | Rubber strap | Stainless steel bracelet | Stainless steel bracelet |
| 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.
Water resistance explainedWill the glass scratch?
It can, over time. Mineral glass handles daily wear but will pick up fine scratches that sapphire would not.
Sapphire, mineral and acrylic comparedDoes it need a battery?
Yes. It is quartz, so expect a battery change every two to three years at a jeweller.
Quartz, automatic and solar comparedCheapest place to buy
Both F.Hinds and Goldsmiths list it at £199, so choose on delivery and warranty rather than price.
More Casio watches like the All Black Metal Cover
In stock, and close on style and price










