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Casio G-SHOCK GBM-2100-1AER Solar Black Resin Strap Watch - W17565
Ref. GBM-2100-1AER
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 129 Casio watches in stock.The GBM-2100 sits at the top of the CasiOak lineage — above the original resin GA-2100 and the metal-bezel GM-2100 — by adding Tough Solar charging and Bluetooth synchronisation to the octagonal form that made the family popular. The Bluetooth link means the watch sets itself to atomic accuracy via a paired phone rather than relying on the owner to adjust it, and solar charging means the battery question simply stops arising. At 11.9mm thick it is notably flat for a G-Shock with this level of capability, and at 72 grams the bio-based resin core keeps the stainless steel-shrouded case from feeling like armour. The dial pairs conventional analogue hands with an inverted LCD window beneath them; in angled or low light the Super Illuminator fires both zones independently, which is more useful than a single backlight covering neither properly. The strap uses quick-release spring bars, so changing it needs no tools — a small detail, but one that matters the second time you want a different look.
- Reference
- GBM-2100-1AER
- Brand
- Casio
- Collection
- G-Shock
- Case size
- 44.4mm
- Case thickness
- 11.9mm
- Lug width
- 16mm
- Case material
- Resin
- Case shape
- Octagonal
- Dial
- Black
- Crystal
- Mineral
- Movement
- Solar
- Functions
- Chronograph, Day-date, Stopwatch, Countdown timer, Alarm, Backlight, World time, Solar powered, Bluetooth, Dual display
- Water resistance
- 200m
- Bracelet / strap
- Rubber strap
- Strap colour
- Black
- Clasp
- Buckle
- Lume
- Luminous
- Retailer
- F.Hinds
Additional specifications
- Lug-to-lug
- 49.3mm
- Warranty
- 2 years
- Strap
- Interchangeable
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
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
- 49.3mm lug-to-lug keeps the 44.4mm case wearable
- Luminous hands and markers for low light
- Second time zone for travelling
- One of Casio's more premium watches
Worth knowing
- 44.4mm sits at the larger end
Compare alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification |  GBM-2100-1AER |  RA-TX0202B10B |  MTRH2S601 |
|---|---|---|---|
| Price | £229 | £219 | £250 |
| Case size | 44.4mm | 42.8mm | 44mm |
| Water resistance | 200m | 200m | 100m |
| Movement | Solar | Solar | Solar |
| 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.
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.
What size strap does it take?
16mm. 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 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
Both F.Hinds and Goldsmiths list it at £229, so choose on delivery and warranty rather than price.
Who are F.Hinds?
F.Hinds has been run by the same family since 1856 and is now in its fifth generation, with more than 115 shops across England and Wales. They are a member of the Responsible Jewellery Council and an Authorised Diamond Dealer.
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