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Casio F-B100W-1AEF Black Activity Tracker - W17634
Ref. F-B100W-1AEF
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Stepping up in the same dial colour
The F-91W has been in continuous production since 1989, and Casio has largely left it alone — which makes the F-B100W the more interesting move. Released in 2024, it takes the rectangular resin silhouette that defined the original and rebuilds it around a Bluetooth link to your phone, so the time sets itself automatically rather than relying on the owner to nail it by hand. The step counter adds a progress graph directly to the segmented LCD, fitting activity tracking into the same display layout without expanding the case beyond what a 38.1mm rectangular watch naturally carries. At 26 grams the F-B100W is barely there on the wrist, and the symmetrical pushers on both sides of the case give it a cleaner profile than the original's asymmetric layout. The amber LED backlight can be set to hold for 1.5 or 3 seconds — a small but considered upgrade over the pinpoint bulb that lit older models — and the bio-based rubber band sits on a standard buckle that anyone familiar with Casio will adjust in seconds.
- Reference
- F-B100W-1AEF
- Brand
- Casio
- Collection
- Casio
- Case size
- 38.1mm
- Case thickness
- 8.8mm
- Case material
- Resin
- Case shape
- Rectangular
- Dial
- Black
- Crystal
- Mineral
- Movement
- Automatic
- Functions
- Stopwatch, Countdown timer, Alarm, Backlight, World time, Bluetooth, Step counter, Digital display
- Bracelet / strap
- Rubber strap
- Strap colour
- Black
- Clasp
- Buckle
- Lume
- Luminous
- Retailer
- F.Hinds
Additional specifications
- Lug-to-lug
- 41.9mm
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 5 collections
This watch appears in Automatic Watches (1,858), Watches Under £100 (759), Rectangular & Square Watches (516), Automatic Watches Under £500 (373) and All Black Watches (356).
Manufacturer’s guarantee
What the specifications mean
A mechanical watch for everyday wear.
Strengths
- 38.1mm suits most wrists
- 8.8mm is unusually slim for a 38.1mm case
- 41.9mm lug-to-lug keeps the 38.1mm case wearable
- Luminous hands and markers for low light
- Second time zone for travelling
Casio F-B100W-1AEF Black Activity Tracker alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | F-B100W-1AEF | 47516/GD/TUR | RA29-2182 |
|---|---|---|---|
| Price | £55 | £65 | £65 |
| Case size | 38.1mm | 38mm | 40mm |
| Water resistance | — | 50m | — |
| Movement | Automatic | Automatic | Automatic |
| Strap | Rubber strap | — | Silicone strap |
| This watch |
|
|
Your new watch
Frequently asked questions, and things you should know about this watch
Will 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 comparedWill it fit my wrist?
Lug-to-lug is 41.9mm, which suits wrists from roughly 15cm (6 inches) upward.
Lug-to-lug decides fit more than case diameter does.
How to size a watch to your wristIs it a men's or women's watch?
Listed as unisex, and at this size it suits any wrist that takes the dimensions.
Cheapest place to buy
F.Hinds is the only UK retailer we track stocking this reference, so there is nothing to compare it against today.
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