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Casio G-SHOCK GM-B2100BD-1AER Solar Bluetooth Black IP Bracelet Watch - W17649
Ref. GM-B2100BD-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 136 Casio watches in stock.The GM-B2100BD marks the first time the 2100 line — itself a direct descendant of the DW-5000C, the original G-SHOCK from 1983 — has been built entirely in metal. The octagonal case form and the dimpled bracelet links are lifted straight from that 1983 reference, but here they are realised in black ion-plated stainless steel rather than resin, which changes the register of the watch considerably. The screw-back case carries the shock resistance the line has always promised, and high-density mounting keeps the analogue-digital module to 12.8mm — slim enough that the bracelet drapes rather than stacks. At 165g it is a substantial thing on the wrist, and it wears like one: the all-black finish reads as a single coherent object rather than a collection of parts. Bluetooth sync through the Casio app keeps the hands true without manual correction, and Tough Solar means that under normal light exposure the watch looks after its own energy indefinitely.
- Reference
- GM-B2100BD-1AER
- Brand
- Casio
- Collection
- G-Shock
- Case size
- 44mm
- Case material
- Black PVD
- Case shape
- Octagonal
- Dial
- Black
- Crystal
- Mineral
- Movement
- Automatic
- Functions
- Date
- Water resistance
- 200m
- Bracelet / strap
- Stainless steel bracelet
- Strap colour
- Black
- Clasp
- Three-fold clasp
- Lume
- Luminous
- Retailer
- Goldsmiths
Additional specifications
- Weight
- 165g
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 (84), Back in Stock (4,683), Stainless Steel Watches (3,109), Automatic Watches (1,756), Watches 44mm and Over (827), Sports Watches (800) and Dive Watches (568).
Manufacturer’s guarantee
Best of 2 retailers
What the specifications mean
A mechanical 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 G-SHOCK GM-B2100BD-1AER Solar Bluetooth alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | GM-B2100BD-1AER | SPB101J1 | 98A273 |
|---|---|---|---|
| Price | £549 | £546 | £489 |
| Case size | 44mm | 45mm | 44mm |
| Water resistance | 200m | 200m | 200m |
| Movement | Automatic | Automatic | Automatic |
| Strap | Stainless steel bracelet | Stainless steel bracelet | Stainless steel bracelet |
| Power reserve | — | 70 hours | 42 hours |
| This watch | Closely matched | Closely matched |
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?
No. It is automatic — the motion of your wrist winds it, and there is no cell to replace.
Quartz, automatic and solar comparedIs it a men's or women's watch?
Listed as men's.
Cheapest place to buy
Both F.Hinds and Goldsmiths list it at £549, so choose on delivery and warranty rather than price.
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