Features Built-in GPS & heart rate monitor Tracks distance / calories / sleep / Sp O / health View smartphone messages & notifications Up to 10 days battery life Water resistant It monitors your heart rate 24 hours a day, so you will be alerted if anything is out of the ordinary The Sp O2 level indicates the amount of oxygen in your blood - giving you extra peace of mind Choose from 100 workout and 17 professional modes, including HIIT and Yoga, and set a goal to aim for It uses 4 major positioning systems including GPS - providing you with better position tracking and more precise fitness data See just how well you slept with sleep monitoring, including details on deep, light, and REM sleep stages