This SportWatch has a GPS powered by TomTom and a Nike+ sensor that tracks the distance covered, pace, time and number of calories burned during your jogging or workout. Both the GPS and the Nike+ sensor seamlessly calibrate to provide accurate stats. The TomTom sportwatch GPS also has a Run Reminder that can be used as a wake-up alarm. This water-resistant sportwatch pinpoints your location and lets you record your pace, speed and distance. It has ample memory to store Nike+ history (up to 50 runs) and other personal records. You can share your run activity on Facebook and Twitter. Its powered by a rechargeable battery that works for 8 hours on 1 charge. Just plug the watch into your computers USB port for easy uploading and recharging. A Polar Wearlink+ transmitter (sold separately) provides information about your heart rate. You can use it while jogging, cycling, hiking or working out at the gym.