Nike+ SportWatch GPS Powered by TomTom (Volt/Black) Water resistant Nike+ SportWatch features TomTom GPS for accurate speed and distance information, indoors or out even if the GPS signal gets interrupted Tap display: simply tap the display to mark up to 50 laps during your run and activate the backlight 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 GPS & sensor both turned on, up to 50 days of standby power. Personal coaching features help keep you at your best-reminds you to run and remembers your records 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