Multiple Sports Modes This premium watch features 14 different sports modes in addition to daily activity tracking, like Run, Run Indoor, Walk, Trail Run, Cycling, Indoor Cycling, Elliptical Trainer, Climb, Pool Swimming, Openwater Swimming, Triathlon, Skiing, Tennis and Soccer. Run Walk Cycling Pool Swimming Soccer Elliptical Trainer Climb Trail Run Triathlon Tennis VO2max Fitness Level Analysis Powered by Firstbeat’s heart rate analytics engine, you can access your cardiorespiratory fitness level in terms of VO2max. VO2max describes the ability of the body to utilize oxygen to transform nutrients into energy. With VO2max functionality, you can access vital physiological information, tailored coaching guidance, gain workout motivation, and benefit from the same scientifically personalized training insights used by professional athletes. Designed for athletes aspiring to improve performance and better understand their physiological data, we offer three important training tools. Training Effect highlights the impact that specific activities have on the development of aerobic performance capacity. Recovery Time recommends down time between each activity to maximize the benefit of each session. Training Load keeps track of the combined physiological impacts of all activities over the past 7 days. Up to 5 Days Battery Life Amazfit Stratos comes with a staggering 5 day battery life on a single charge, saving the trouble to charge it frequently. In a GPS-enabled sports mode you still receive a continuous 35 hours of battery life, sufficient for a 100km trail run for instance. Onboard Music You can listen to music you like while running with the onboard music storage being able to leave your phone behind. Simply load your favorite music onto the watch, connect it directly to your Bluetooth headphones or earbuds, and you are good to go. Bluetooth Music Call Notifications Message Notifications Silent Alarm Amazfit Watch App 2.0 The new Amazfit Watch App 2.0 allows you to synchronize data, check daily activity data and exercise records, adjust installed watch widget, import sports tracking map data and more. The App also supports the synchronization of your exercise data to third-party Apps.