Fitbit Charge HR Wireless Activity Wristband (Black, Small (5.4 - 6.2 in)) About the product Charge HR syncs automatically and wirelessly to tablets, computers and 150+ leading iOS, Android and Windows smartphones using Bluetooth 4.0 wireless technology. Syncing to computers requires Internet connection and USB port. Syncing to mobile devices requires Bluetooth and Internet connection. Syncing range: 20 feet Water Resistance: Charge HR is sweat, rain and splash proof. However, the device is not swim proof or showerproof. With any wearable device, it’s best for your skin if the band stays dry and clean. Battery life: lasts up to 5 days. Radio transceiver: Bluetooth 4.0 Warning: Do not use if you have a pacemaker or other internal, or implanted medical device. Not intended for use by children under 13. Always consult your physician. Slippery when wet We recommend charging your device every few days to ensure you are always tracking. Charge time: One to two hours Syncs with Windows Vista and later, Mac OS X 10.6 and up, iPhone 4S and later, iPad 3 gen. and later, and leading Android and Windows devices From the manufacturer View larger Fitbit Charge HR. View larger View larger Mobile Online Tools Sync stats wirelessly and automatically to your computer and 120+ leading smartphones—including Android, iOS and Windows. Set goals, log food, see progress, analyze trends and earn achievement badges through your mobile and online dashboard. Share and compete with friends and family on the leaderboard and in New Fitbit challenges. Wireless Heart Rate + Activity Wristband Make every beat count with Charge HR—a high-performance wristband with automatic, continuous heart rate and activity tracking right on your wrist. See heart rate all day and during workouts to get more accurate calorie burn, reach your target workout intensity and maximize training time. Track steps, distance, floors climbed and sleep quality and more, and stay connected with Caller ID and time of day on display. Charge HR also wirelessly syncs to your smartphone and computer so you can monitor your trends and get the motivation you need to push yourself further—every step, every beat, every day. PurePulse Heart Rate. Activity Tracking. Auto Sleep + Silent Alarm. Exercise Tracking. Caller ID. OLED Display. View larger PurePulse Heart Rate Get continuous, automatic, wrist-based heart rate monitoring and see simplified heart zones—with no uncomfortable chest strap. Activity Tracking Track steps taken, distance traveled, calories burned, floors climbed and active minutes. Auto Sleep + Silent Alarm Automatically monitor how long and how well you sleep and set a silent, vibrating alarm. View larger Exercise Tracking Record workouts in Exercise Mode, then see detailed workout summaries on your smartphone. Caller ID See call notifications right on your wrist when your phone is nearby. OLED Display Bright display shows daily stats and time of day right on your wrist.