Casio G-Shock GULFMASTER Twin Sensor Moon Data Tide Graph GN-1000B-1A Men's WatchCasio G Shock GULFMASTER Twin Sensor Moon Data Tide Graph GN 1000B 1A GN1000B 1A Men's Watch The GULFMASTER has been designed and engineered to withstand the rigors of professional maritime activities and now, with this Twin Sensor model, you can track directions and temperature to keep you informed about the environment you are heading towards. Added with the Tide Graph, and a Moon Age indicator, you can check if its a favourable time that you are