Nike+ SportWatch GPS Powered by TomTom (Black) Water resistant Nike+ SportWatch features TomTom GPS for accurate speed and distance information, indoors or out--even if the GPS signal gets interrupted Track your time, distance, pace or speed, beats per minute (BPM) heart rate (with optional HRM sensor sold separately by Polar), and calories burned; view your mapped route with pace data/changes in elevation on Nikeplus.com, Stopwatch feature Track NikeFuel on Nikeplus.com after every run; Time/Date set feature Rechargeable lithium polymer battery charges via USB, provides eight hours of run time with the GPS and sensor both turned on, up to 50 days of standby power Join challenges and connect with friends as a member of Nikeplus.com-view/share routes, find popular running areas, share activity on Facebook or Twitter