The Charge HR houses an OLED display that lets you see your progress in real-time throughout the day. Charge HR is sweat, rain and splash proof . This wrist-worn activity monitor tracks how many steps you take, your distance traveled, calories burned, floors climbed, and how many minutes you stay active. Thanks to its onboard PurePulse technology, the Charge HR also provides continuous and automatic heart rate data. You can use this heart rate data to monitor your intensity, analyze the effectiveness of your activities, maximize your workouts, and more. In addition to activity tracking and heart rate data, the Charge HR is built with Caller ID, so you can see your incoming calls when your phone is nearby. Additionally, it features sleep tracking capabilities and is equipped with a silent vibrating alarm to help you wake peacefully.Automatically recognizes when you exercise & records it in the Fitbit app .You can sync your stats wirelessly to compatible mobile devices and computers. Simply download the fitbit app to sync with a smartphone, which is available for iOS, Android, and Windows Phone devices. The Charge HR’s built-in rechargeable battery lasts up to 5 days before needing to recharge. The Charge HR automatically syncs your stats wirelessly to your computer and smartphone, so you can see your progress on-the-go and see detailed charts and graphs for tracking your trends over time. Sync stats wirelessly and automatically to your computer and over 150 leading smartphones .Download the Fitbit mobile app to sync with a smartphone, which is available for iOS, Android, and Windows Phone devices.