Make every beat count with Fitbit Charge -the all-new heart rate and fitness wristband built for all-day, workouts and beyond. PurePulse continuous heart rate makes it easy to maximize workouts, better track calorie burn and get a snapshot of your cardio fitness level, while all-day activity and auto sleep tracking, lets you see how your whole routine adds up. Record your workouts with multi-sport modes to see real-time workout stats on screen, or rely on SmartTrack to automatically record select exercises for you. The large OLED display helps you stay connected with call, text and calendar alerts, stay active with Reminders to Move, and find moments of calm with personalized guided breathing sessions. Plus, you can find a look that fits your style with customizable clock faces and interchangeable bands. With more advanced features in a sleeker package, it’s the motivation you need to push yourself further-every step, every beat, every day

• 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, its best for your skin if the band stays dry and clean.
• Battery life: lasts up to 5 days.
• Radio transceiver: Bluetooth 4.0
• 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

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

From the Manufacturer:
Certain features like Auto Sleep Tracking and SmartTrack may be disabled when using this accessory. Classic accessory bands are the recommended accessory for high intensity workouts and sleep tracking. Do not wear the Flex 2 Pendant accessory while sleeping or during high intensity activity, as doing so could create a choking hazard. Flex 2 Pendant accessories contain magnets. Magnets may interfere with pacemakers, defibrillators, or other medical devices. Consult your physician and the manufacturer of your medical device before using to determine if these accessories are safe for you. If the accessories may be interfering with your pacemaker, defibrillator, or other medical device, do not wear the accessories.

Buying Guide:

• Move it up: Since blood increases further up your arm, wear your tracker higher on your wrist to improve the heart rate signal during workouts. Start by moving the device up to three finger widths above your wrist bone, then experiment with slightly lower placement.
• Keep it secure: The less your tracker moves during exercise, the more chance you have of maintaining a heart rate signal throughout the activity. Do not wear the band too tightly, as this can restrict blood flow and goes against our wear and care guidelines.
• Hold steady for ten seconds: High intensity exercises or activities that cause you to keep your wrist bent (like push-ups) or move your arms vigorously (like dance) may interfere with heart rate signals. If you stop seeing a signal during these types of activities, hold your wrist steady for ten seconds during breaks to get your reading.