Tough. Solar. Bluetooth. Analog – this is the Casio Casio G-Steel GST-B100X-1A. Connected watches are growing in popularity – with the introduction of low energy bluetooth connections, persistently connected cell phones, and more and more information hitting us from all angles, the ability to keep your watch connected with the rest of your devices is more relevant than it every was.

In keeping up with modern technology, adding class-leading ruggedness, and using advanced materials, with a touch of class, Casio has released the Casio Casio G-Steel GST-B100D. This rugged G-Shock is all-analog, but hides a bluetooth connection, solar charging, and a host of other features.

First Impressions

On first glance, this thing is relatively big! But after taking it out of the box, I realize that it’s actually not that huge – it’s noticeable slimmer than I expected, and the soft rubber strap contours nicely. The hands on the dial are large and easy to read, and the rest of the smaller dials are relatively easy to read too. The layout is simple, although a few of the mode and activity indicators take a bit of getting used to. The carbon fiber bezel is great – it has that 3D kinda shine that makes it look great, and the visible layers are certainly cool. I love the subdued black on black bezel and band – a low key look, packing a good amount of power.

Fit and Finish

As you’d expect from a higher end Casio, fit and finish are great – the strap attaches securely to the watch, the buckle matches the case color exactly. The carbon fiber bezel looks and feels great, and is perfectly smooth, except for nicely embossed button labels. Also, the buttons are relatively clearly marked, with the bluetooth logo embossed on the connection button.
As soon as the watch is exposed to light, it starts ticking away. And as soon as it’s been paired with the smartphone app, it automatically synchronizes and sets the time – pretty easy setup.

Pairing the watch with the smartphone app is easy. The watch uses BT4 beacon technology, so pairing happens directly in the app – no need to go through the settings app on your phone. Once paired, syncing time can happen with the phone in your pocket, and connecting to the watch is as easy as holding the bluetooth button for two seconds.

On The Wrist

Although chunky, the watch is surprisingly wearable. The rubber band is comfortable and fits well, the buckle is secure, and the watch is actually somewhat slim. Once it warms up on the wrist, it’s actually a pleasure to wear all day. I even slept with it on for a few nights while camping in the rocky mountains, and it’s certainly comfortable at night too.

Time is easy to read from the main dials – although there are no numerals – not that much of an issue though. Since the watch is all analog, world time and other functions are indicated on smaller sub dials. This did pose a small issue for readability when the main hands were sitting over the hands of the smaller dials – on one occasion I was timing my parking meter, and couldn’t tell how long I had left on the timer because the hour hand was sitting directly over the smaller subdial used for the timer function.

In order to indicate details of each feature, the watch repurposes the main dial and sub dial,. This means that when switching modes, it takes a few seconds for the hands to wind around to indicate the mode details. And then when switching back to the time display, the hands wind around again to indicate the time. Not a major issue, but still it takes a few pauses to wait for the watch to catch up. Luckily, it’s solar powered, so I’m not really worried about running down the batteries.

Using the extended features of the watch – world time, timer, stopwatch, alarm – is doable. But the dials are small, and the button combinations somewhat cryptic. The features certainly do work, but I wouldn’t want to wear this watch if I was going to be relying on the features heavily – they’re just not as easy to use as they need to be for every day use. Luckily, timers, alarms, etc are all handled on my smartphone.

I realize there’s a smartphone app to ease the use of the watch features, such as setting the alarm – but if I’m going to be fiddling with my phone, why just not use the alarm app running on my phone?

Standout Features

  • Carbon Fiber Bezel – L0oks very nice, feels great.
  • Atomic time keeping via internet – always on time, sets itself every night. Never late!
  • App enables use of features in an easier interface than clicking buttons on the watch
  • The LED light is bright! Enough for wayfinding in the middle of the night, or searching for a dropped toothbrush in the tent, or something.
  • Tough Solar – a staple on GShocks, but great nonetheless.

Ideas for V2.0

If I could iterate on the ideas this watch started, and give the designers a few more ideas for the future, here’s what I’d consider:

  • Although I love the use of an app to set watch features, I really don’t think that the app adds enough functionality to the watch to really be worth it. Sure, it makes setting up the features easier, but I could do this on the watch directly.
  • It’s nice to have the watch set itself – but this relies on both a bluetooth connection to my smartphone and an internet connection to time servers to get the correct time. For a watch, this seems like a complicated chain just to set the time. I’d much prefer the atomic timekeeping other gshocks use, tuning into atomic clock radiowaves. Maybe if there was a bit more customization here, it might be useful. Like allowing me to set a custom time server, or other fun stuff to tinker with how the watch sets itself. The time setting feature is really only useful when you’re in civilization and have your phone on you. For a rugged outdoors watch, I’d like to see features that work in the backcountry without a connection.
  • Even better, give it a GPS connection for setting the time and time zone.
  • Use the main hands to show notification numbers, or other bluetooth connected data, using the subdial for the current local time. How about showing me current fitness data being collected by the pedometer on my phone? How close I am to a health goal? Other fitness data? How about using the hands to indicate how many messages I have, local weather and temperature, stock data, or any of millions of sources. Since you’re connecting the phone to an app, there’s so much you could do here.
  • That LED light is bright! Let it spell out SOS in morse code, strobe mode, or other lighting effects. Also, what about a dimmer mode?
  • Sync the watch timers with timers in the app, and use the app to show large display, splits, milliseconds, etc. Currently the stopwatch only counts in 1-second increments, How about using the app to show better resolution?
  • Use the buttons on the watch as a “clicker” to advance slides, go to the next part of a workout, etc. When I’m working out and want to change exercises in the app I’m using, I’d love to just click a button on my watch.
  • Use phone finder to simulate a ringing phone, to get me out of  a sticky situation.
  • Connect that phone finder button (long press) to IFTTT and let me trigger any IFTTT recipe with that button – like getting a call to get out of a sticky situation, lock my doors, set my thermostat to away mode, log something in a spreadsheet, or whatever.
  • Give me more information about the solar charing status of the watch. Better yet, re-appropriate solar charging data into sun exposure data for the wearer. No, don’t make it a “medical device”.. but some basic exposure or intensity info would be nifty. Also have the app show battery percentage or remaining run time and charge time, as well as battery cycles and battery health. If I was taking this watch into the field, and suspected the battery was wearing out, that would be an issue. Tell me the health of the batter.. or make it field replaceable.


  • Case / bezel material: Resin / Stainless steel
  • Resin Band
  • Neobrite
  • Screw Lock Crown
  • Shock Resistant
  • Carbon fiber bezel
  • Sapphire Glass with non-reflective coating
  • 200-meter water resistance


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ByJeffrey Donenfeld

Wrist Watch Review Writer Jeffrey Donenfeld lives in Colorado and reviews products at his website. An accomplished adventure traveler, antarctic expedition director, and rescue scuba diver, Jeffrey has tested and reviewed watches in a multitude of challenging environments. Jeffrey loves exploring design, construction, materials, and utility aspects of horology, and gets a kick out of both classics as well as fresh new ideas. He typically tests extensively watches he writes about, and provides readers with a real-world, practical take on diverse timepieces. In addition to writing about time, Jeffrey also works as a venture capital investment manager at a growing startup accelerator in Boulder, Colorado. In his free time he travels (70+ countries and counting), snowboards, rock climbs, runs, sails, scuba dives, and occasionally relaxes.

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