Constructed to U.S. military standard 810G for thermal, shock and water resistance (rated to 100 meters). Built-in 3-axis compass and barometric altimeter plus multiple global navigation satellite systems (GPS, GLONASS and Galileo) support helps track in more challenging environments than GPS alone. Monitor your heart rate, activity and stress; train with preloaded activity profiles. Stay connected with smart notifications and automatic data uploads to the Garmin Connect online fitness community. Use the TracBack feature to navigate the same route back to your starting point; use the Garmin Explore website and app to plan your trips in advance. Battery life: up to 14 days in smartwatch mode, up to 14 hours in GPS mode, up to 35 hours in UltraTrac battery saver mode (depending on settings).