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.

SIZE & MATERIALS
Band Type: Bio-based resin band
Case and Bezel material: Carbon / Bio-based Resin
Size: 59 × 54.7 × 15.7 mm
Colour: Grey
Compatible band size: 145 to 215 mm
Glass: Mineral Glass
Weight: 71 g

FEATURES
Water resistance: 200 M
World time:
• World time
• 31 time zones (48 cities coordinated universal time)
• City code display
• Daylight saving on/off

Timer:
• Countdown timer
• Measuring unit: 1 second
• Countdown range: 60 minutes
• Countdown start time setting range: 1 to 60 minutes (1-minute increments)

Light:
• LED light (Super Illuminator)
• Afterglow

Calendar:
Full auto-calendar (to year 2099)
Stopwatch:
• 1/100-second stopwatch
• Measuring capacity: 23:59'59.99''
• Measuring modes: Elapsed time, split time, 1st-2nd place times

Alarm/hourly time signal:
5 daily alarms (with 1 snooze alarm)
Hourly Time Signal
Mute feature:
Button operation tone on/off
Battery display/alert
Low Battery Warning

SPECIFICATIONS
Construction:
• Shock Resistant
• Carbon Core Guard structure

Time Adjustment:
Bluetooth: Connects to a smartphone and automatically adjusts the time
Power supply and battery life:
Tough Solar (Solar powered)

Surface treatment:
• Other: Neobrite
• Screw Lock Crown

Light Color: White
Accuracy: ±15 seconds per month
Other features:
• 12/24-hour format
• Regular timekeeping:
∙ Analogue: 3 hands (hour, minute (hand moves every 10 seconds), second)
∙ Digital: Hour, minute, second, pm, month, date, day