Casio G-Shock MASTER OF G AIR GRAVITYMASTER Bluetooth¶ô¶÷ Tough Solar Watch GRB300-1A GR-B300-1A

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 fiber-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 color scheme dotted with color accents on the dial and buttons evokes the look of a cockpit instrument panel, while dark color 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.

Case / bezel material: Carbon / Bio-based resin
Bio-based resin band
Mineral Glass
Neobrite
Shock Resistant
Carbon Core Guard structure
Screw Lock Crown
200-meter water resistance
LED light (Super Illuminator)
Afterglow
LED:White
Tough Solar (Solar powered)
Mobile link (Wireless linking using Bluetooth®)
Dual time (Home City time swapping)
1-second stopwatch
Measuring capacity: 23:59'59.
Measuring modes: Elapsed time, split time
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)
Daily alarm
Battery level indicator
Power Saving (hands stop to save power when the watch is left in the dark)
Full auto-calendar (to year 2099)
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)
Accuracy: ±15 seconds per month (with no mobile link function)
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)
Size of case : 59 × 54.7 × 15.7 mm
Total weight : 71 g