G-SHOCK

GRB300-8A2

$699.00
Size Chart

The sky’s the limit! Introducing the GRAVITYMASTER GR-B300, a piece of aviation-inspired professional gear designed to work even in the harshest environments, from the G-SHOCK MASTER of G line.

The GR-B300 features a Carbon Core Guard structure, which delivers the shock-resistance, rigidity, and corrosion-resistance of carbon material used in aircraft fuselages. The carbon fibre reinforced resin case and the seamless bezel design inspired by next-generation aircraft come together in a bold and powerful form. 

Envision the world through a pilot’s eyes with the flight log memory function for recording current location and time, as well as dual-time simultaneously displaying the time in two time zones. In addition, simply tap on the app to instantly switch between the time back home and local time — a practical function to make traveling abroad that much smoother. Large, dimensional index marks and a metal bezel accentuating the large watch face exude functionality, enhancing the visibility that is so important for pilots, whose job demands intuitive reading of time. The rotary disc indicator at the 9 o’clock position uses a dual-coil motor to ensure smooth rotation and functional beauty. The indicator not only rotates to display alarm on/off and stopwatch; it functions as a battery level indicator as well. The high-contrast black and white colour scheme dotted with colour accents on the dial and buttons evokes the look of a cockpit instrument panel, while dark colour variations express the practical functionality of an aviation worldview. 

Key resin components used in the case, bezel, and band are made with bio-based resin, a material expected to help reduce environmental impact.

2 year warranty

Gravitymaster

Basic Information
  • Band
    Bio-based resin band
  • Case and bezel material
    Bio-based Carbon / Bio-based resin
  • Case size (L × W × H)
    59 × 54.7 × 15.7 mm
  • Construction
    Shock Resistant, Carbon Core Guard structure
  • Power supply and battery life
    Tough Solar (Solar powered)
  • Time adjustment
    Bluetooth: Connects to a smartphone and automatically adjusts the time
  • Water resistance
    200-metre water resistance
  • Weight
    71 g

Exterior
  • Compatible band size
    145 to 215 mm
  • Crown
    Screw Lock Crown
  • Glass
    Mineral Glass
  • Other
    Neobrite

Smartphone Link / App Connectivity Features
  • App connectivity feature
    Auto time adjustment, Easy watch setting, Approximately 300 world time cities, Flight log, Phone finder
  • Apps
    CASIO WATCHES
  • Smartphone link feature
    Mobile link (Wireless linking using Bluetooth®)

Features
  • Accuracy
    Accuracy: ±15 seconds per month (with no mobile link function)
  • Alarm / hourly time signal
    Daily alarm
  • Battery display alert
    Battery level indicator
  • Calendar
    Full auto-calendar (to year 2099)
  • Energy saving feature
    Power Saving (hands stop to save power when the watch is left in the dark)
  • Light
    LED light (Super Illuminator)
    Afterglow
  • Other features
    Date display
    Day indicator
    Regular timekeeping:
    Analog: 3 hands (hour, minute (hand moves every 10 seconds), second), 3 dials (dual time hour and minute, dual time 24-hour, day)
  • Run time
    Approx. battery operating time:
    5 months on rechargeable battery (operation period with normal use without exposure to light after charge)
    18 months on rechargeable battery (operation period when stored in total darkness with the power save function on after full charge)
  • Stopwatch
    1-second stopwatch
    Measuring capacity: 23:59'59.
    Measuring modes: Elapsed time, split time
  • Timer
    Countdown timer
    Measuring unit: 1 second
    Countdown range: 24 hours
    Countdown start time setting range: 1 minute to 24 hours (1-minute increments and 1-hour increments)
  • World time
    Dual time (Home City time swapping)
User Manual – Module 5719

Seamless design offering functional beauty

An organic form inspired by next-generation aircraft is expressed with the seamless exterior design. A sense of unity is achieved by connecting the exterior surfaces, from the case to the band, smoothly and seamlessly. This design creates a tough, cutting-edge look, seemly for a new addition to the GRAVITYMASTER line.

3D face design for enhanced readability

The large-diameter, triple-layer dial with a sense of depth ensures readability for pilots, whose job demands intuitive reading of time. In addition to large, dimensional index marks and inset dials inspired by instrument panels, the metal bezel accentuating the large watch face ensures this design exudes functionality.

Dual time: Simultaneous display of time in two cities

The main dial and inset dial simultaneously display times in two cities located in different time zones. A dedicated app makes it easy to configure world time settings. Switching between home time and world time is a snap, as well. This watch puts accurate time management just a fingertip away.

Colouration evoking the look of a cockpit

A high-contrast black and white colour scheme enhances the visibility of the watch hands and index marks, components responsible for the most vital watch functions. Red and blue colour variations are offered as well, with the red model inspired by the display colour of a cockpit instrument panel’s nighttime illumination, and the blue, that of a head-up display (HUD). These distinctive combinations of colour deliver practical functionality expressing an aviation worldview.

Flight log: Helpful for flight history management

Sync the watch with a smartphone and press a button on the watch to record the current time and position on a map within the dedicated app — a useful function for managing flight logs with details including times and locations of departure and arrival. In addition, plotted data can be grouped for batch management of travel record details including points of departure, transit points, and home destinations.

Layer Guard and Carbon Core Guard structures: Featuring innovative combinations of materials

The intricately shaped bezel employs integrated moulding and has two rings — a metal ring and a urethane ring — installed beneath it. This combination of materials gives the bezel — a structural component — a refined visual presence that embodies the intricacy and sophistication of next-generation aircraft. The case is made with carbon fibre-reinforced resin, a material delivering both strength and lightness. The side buttons have anti-slip texturing inspired by hazard warning stripe tapes, and the guards beneath the buttons have been eliminated for even better operability.

Feature List

  • Black icon of a watch hitting a flat surface with motion lines indicating a shock or impact.

    Shock resistant

  • Black icon of a person snorkeling with the number 20, representing a 20-bar pressure rating for water resistance.

    20 bar water resistant

  • Minimalist black icon of a person walking next to a simple clock face, representing punctuality or time management.

    Keeps yourself in time

  • Black icon of a smartwatch charging via solar energy with a battery level indicator and sun rays.

    Stable solar power

  • Black and white icon of a smartphone syncing time with an analog wristwatch via a wireless connection.

    Easy to operate via smartphone

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