The Fenix 3 was designed for the outdoor adventurer. It’s built to take the roughest conditions and with its EXO antenna it can get a fix faster to the GLONSS satellites. It is also packed with training features to tell you about your form and fitness. The first is the VO2 max estimator. When used with a heart rate monitor, fenix 3 crunches data, including your running speed, beats per minute and heart rate variability to estimate the maximum volume of oxygen you can consume per minute. This watch is a must have in the gym or in the great outdoors.