or communicating with helicopter/plane 
did you know one of Breitling watch has short-wave emergency transmission?
see the big knob on right-bottom side of the watch? you unscrew it and pull it out. It will emit the emergency transmission for up to 24 hrs, I believe.
Breitling
a cool story about this - several years ago - a millionaire went out in hot-air balloon to fly around the world. He had a mishap during the flight and it plunged into sea. He had that same watch and he got rescued when a plane flew over. That pilot relayed the message to Coast Guard.
