The sky’s the limit with the gravitymaster grb300, a piece of aviation-inspired professional gear designed to work even in the harshest environments, from the g-shock master of g line. 54mm black bio-based resin case with carbon fiber core high-contrast black and white dial with subtle red color accents evoking the look of a cockpit instrument panel powered by tough solar smartphone linking using bluetooth® black bio-based resin strap with buckle clasp shock resistant and water resistant to 200 meters