Casio G-Shock Gravitymaster GRB300

Quick specs Casio G-Shock Gravitymaster GRB300
Price: $ 300 | € 299 | approx. £ 236 | approx. CHF 265
Size: 59 mm × 54.7 mm
Reference:
GRB300-1A (carbon black/beige)
GRB300-1A4 (black/orange)
GRB300-8A2 (grey/blue)
GRB300EC-1A (black/bit orange)

The Casio G-Shock Gravitymaster GRB300 series is a watch designed with aviators in mind. So apart from precision, it strongly focuses on durability and functionality. Although regular commercial aircraft pilots won’t wear a survival-esque clock like this, military pilots might like it. Especially for its indestructible presence, although it has mineral glass instead of the harder sapphire crystal. The clearly readable indications are a big plus as well.

The Gravitymaster series is part of the Casio G-Shock collection, which began in 1983 with the wish to create an unbreakable watch. Over the decades, the G-Shock has become synonymous with toughness and innovation, and it also has become a kind of a brand in a brand. The Gravitymaster line focuses on aviation-specific needs, combining advanced technology with the durability of G-Shock.

Design of the GRB300 Series

This GRB300 series includes four distinct models: GRB300-1A, GRB300-1A4, GRB300-8A2, and the GRB300EC-1A. Each model features a carbon core guard structure, leveraging carbon materials commonly used in aircraft for enhanced toughness and reduced weight. This is combined with a modern, eco-friendly material called bio-based resin.

It is huge, also thanks to the crown guards and bezel and dial protection. With a case size of 59 millimeters wide and 54.7 millimeters in height, it looks like you need a trained arm to wear it. Its thickness is 15.7 millimeters but all in all the weight is only 71 grams. The whole construction makes it shock-resistant and water-resistant up to 200 meters / 660 feet.

Clear, Easy to Read Dial

The dial layout prioritizes readability, with a high-contrast black-and-white palette. Additional color accents, such as orange, red, and blue, reflect the visual elements of cockpit instrumentation but also help to find the necessary information even quicker. Oversized index marks and what Casio calls an intuitive triple-layer dial improve visibility.

The Gravitymaster is charged with light so the rotary disc at the 9 o’clock position is important. As it indicates the solar charge levels and alarm status. At 12 is a combined function indicator and day of the week indicator. With the first, you can switch between the modes the watch offers. Variating from setting the regular adjustment of time settings to operating the alarm, stopwatch, countdown timer, second time zone indicator, and more.

More Functions of the Gravitymaster GRB300

We just mentioned the second time zone, which is indicated at the 6 o’clock position, with an hour and minute hand. Furthermore, there are about 300 world-time cities programmed to choose from. The watch also sports a fully automatic calendar to the year 2099, as said with days of the week at 12, and a date window between the 4 and 5 o’clock position.

As you can connect the watch to your phone it also has a phone finder function. The app for your phone offers a flight log mode, automatic time adjustments, and setting options. More functions are a radio-controlled (Multiband 6) connection, auto hand home position correction, and LED light.

The Module: the Casio caliber 5719

The GRB300 series uses Casio’s caliber 5719, a quartz movement powered by light the brand calls tough solar technology. This means that the solar cells are more efficient in capturing light from various sources, including low-light conditions like indoor fluorescent lighting. The accuracy of the movement is about +/- 15 seconds per month without using the smartphone connection.

Each GRB300 model features a resin band, a material chosen for its durability and comfort, and here seamlessly integrates with the case.

Pricing of the Casio G-Shock Gravitymaster GRB300

The GRB300 models are priced at 300 dollars or euros. So, it makes sense the model has mineral glass instead of sapphire. With a price like this, given all the functions including a smartphone link, it’s just a bargain. It is not sophisticated nor stylish or otherwise, it’s just pure functionality packed in a rugged case.

Comparable watches in this category are also coming from Japan and include models from Citizen and Seiko. They have alternatives that also focus on aviation, but the GRB300 stands out with its smartphone connectivity and carbon core guard structure. Not universally available in similar price ranges. And if you want a watch with satellite connection for even more survival-ish adventures you end up with one that will be at least four to five times more expensive.