A rugged GPS Watch fit for professional marine activities up to 100 meters depth, it follows U.S. Military Standard 810 which also applies to its heat and shock resistance apart from water. It has a built-in, 3-axis compass; a barometer, an altimeter and multiple global navigation satellite systems. You won’t find US GPS network, GLONASS and Galileo (the only satellite constellation system managed by the civilians) all tucked into the same unit!