Don't just start. Surge with the Fitbit's FB501BKL which shows run time, distance, pace and elevation stats on display. Review routes and split times after you run them, and scroll through workout summaries to stay on track while you train. Maximize training, maintain intensity and monitor calorie burn with automatic wrist-based heart rate monitoring. With continuous heart rate readings, Surge keeps you in the zone all day and during workouts. Built with eight-sensor technology and best-in-class battery life, Surge transitions seamlessly from work to workouts tracking real-time stats like steps, distance, heart rate, active minutes, calories burned, and more, to keep you in the know, on the go.