This has a built-in three-axis compass and barometric altimeter with multiple global navigation satellite systems. The battery life last up to 14 days in smartwatch mode, up to 16 hours in GPS mode, and up to 40 hours in UltraTrac™ battery-saver mode. It monitors your heart rate, activity, and stress and (like all our beloved Garmin picks) it's shock, thermal, and water resistant.
Promising review: "I need four things in a smartwatch: notifications, always on display, battery life, and ruggedness. Things I don't need (that the industry keeps trying to sell me): apps, games, LTE, LCD/OLED screens. Once you've experienced the nirvana of a two-week battery life, mil-spec construction, and a device that isn't designed to beg for your attention every second of the day you'll laugh at other watch users trying to leek a day or two of life from their tiny, fragile wrist cellphones. If you're thinking of getting a new watch and need something that works and plays as hard as you do, get this one. Thanks for making a device people actually need, Garmin!" —Stephen
Get it from REI for $250 (available in two colors).