Get the power of continuous heart rate in Fitbit's slimmest design yet - all day, during workouts and beyond. With heart rate, you can better measure calorie burn, and use zones (Fat Burn, Cardio, and Peak) to find the right workout intenity for your goals. See how working out more can improve your health by comparing your resting heart rate trends to your activity. With sleep stages powered by PurePulse heart rate, automatically track your time spent in light, deep, and REM sleep and take steps toward a better night's rest. Automatically track your steps, distance, calories burned and active minutes. Get Reminders to Move that encourage you to reach an hourly goal of 250 steps. Stay connected with call, text, and calendar notifications on display (when your phone is nearby). With a battery life of up to 5 days, you can worry less about your tracker and focus more on your goals. See your stats and the time of day on a bright OLED tap display. Sync stats wirelessly to 200+ leading smartphones and computers, including iOS, Android and Windows. Use the Fitbit App to track your trends, connect with friends, get personalized coaching, and more. Works with the Fitbit app and dashboard and the Aria Wi-Fi Smart Scale. Water resistant.