Slim Octagonal G-Shock Design
An 11.8 mm case thickness and octagonal bezel give this GA-2100-1A1 its distinctive slim CasiOak profile.
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Updated 4 months ago
Slim analog-digital G-Shock with octagonal bezel and carbon core guard structure.

An 11.8 mm case thickness and octagonal bezel give this GA-2100-1A1 its distinctive slim CasiOak profile.
The watch includes date, day, world time, stopwatch, countdown timer, alarm, hourly time signal, and 12/24-hour format functions.
A carbon/resin case with shock resistance and 200 m water resistance supports daily wear in demanding conditions.
The Casio G-Shock GA-2100-1A1 CasiOak is a slim analog-digital quartz watch with an octagonal bezel, carbon/resin case, resin band, mineral glass crystal, and 200 m water resistance.
The reviewer praised the watch as an attractive, minimalist ana-digi timepiece that successfully bridges the gap between G-Shock fans and traditional watch enthusiasts, though noted legibility issues on the stealth version.
The reviewer highlights the watch's excellent design, slim profile, and legendary toughness, while criticizing the poor legibility of the negative display and the learning curve for its functions.
The review concludes that the CasiOak remains a solid, versatile, and high-value watch that lives up to its hype as a capable daily wearer, maintaining its status as one of the best watches available under $100.
The reviewer was highly impressed by the watch's design and thinness but noted that the negative display model makes it very difficult to read the time in anything other than direct sunlight.
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| Attribute | Specification | Notes |
|---|---|---|
| Band Material | Resin | |
| Band Width | 16 mm | mm |
| Battery Life | 1095 days | days |
| Case Diameter | 45.4 mm | mm |
| Case Material | Carbon / Resin | |
| Case Thickness | 11.8 mm | mm |
| Clasp Type | buckle | |
| Crystal Material | mineral glass | |
| Display Type | analog-digital | |
| Features | date, day, world time, countdown timer, chronograph (stopwatch), alarm, LED light (double LED / Super Illuminator), shock resistant, auto-calendar (to year 2099), hourly time signal, 12/24-hour format, hand shift feature | |
| Gender Target | men | |
| Movement Type | quartz | |
| Power Source | battery | |
| Water Resistance | 200 m | m |

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