Fitbit Charge 4 Fitness TrackerWith Fitbit Charge 4, there’s no limit to how far you can go. This sleek, swimproof tracker is packed with features that help you know your workouts and your body better—like built-in GPS, Active Zone Minutes, a new exercise mode and sleep tracking. Plus, with Fitbit Pay and up to 7-day battery, you get more convenience on the go and more inspiration to reach your fitness goals.**Water resistant to 50M.​ ​Battery life varies with use and other factors;​ up to 5 hours with continuous GPS.Product Features:24/7 HEART RATE - Use 24/7 heart rate to better track calorie burn, optimize workouts and uncover health trends that inspire you to make moves on your health and fitness goals.RESTING HEART RATE - Wear Fitbit Charge 4 all day and night to record and reveal your resting heart rate, track heart rate trends over time, and follow your health and fitness progress.HEART RATE ZONES - Now heart rate zones are personalized based on your age and resting heart rate, so when you’re exercising you get a more accurate understanding of how hard your body’s working.WORKOUT INTENSITY MAP - IN APP ONLY - After outdoor exercise, check your workout intensity map in the Fitbit app to see your heart rate zones throughout your route and learn where you put in the most effort.ACTIVE ZONE MINUTES - With new Active Zone Minutes, your tracker buzzes when you reach your target heart rate zones during exercise, and celebrates when you earn extra minutes outside of exercise.