Fitbit Charge 2 Continuous, automatic, wrist-based heart rate tracking without an uncomforatble chest strap. Easily records runs, biking, weights and more and connect with the GPS on your phone to see real-time stats on display. Get a better understanding of your fitness level and see how you can improve over time with a personalized Cardio Fitness Score. SmartTrack automatically recognizes select exercises (running, biking and more) and records them for you in the Fitbit app. Find moments of calm throughout your day with personalized guided breathing sessions based on your heart rate. Track steps, distance, calories burned, floors climbed, active minutes and hourly activity. Features: • PurePulse Heart Rate Tracking Technology • Tracks Steps, Distance, Calories, & More • Auto Sleep Tracking • Sport Tracking & Exercise Recognition • Interactive OLED Display • See Stats, Time of Day, Exercise Mode • Connected GPS • Smartphone Notifications • App for iOS/Android/Windows Phones • Battery Lasts 5 Days on a Charge