TAVA M4 Bluetooth Smart Band Waterproof Heart Rate Monitor Blood Pressure Fitness Tracker M4 water proof Smart fitness Band with Bluetooth or Heart Rate sensor,Activity Records, Sleep Monitor, Calory Burned, Rejected Calling, Alarm, Blood Pressure, Message, USB Charging Supports smart phones, Tablets and PC's and also support Android and iOS Color- Black - It has features such as calling function which enables you receive a call and disconnect it, you can also send and receive messages through it but only supported to android Phones for which you need to download app Waterproof level: IP67, Industry's Best. Charge the device fully before first use.Compatibility: Requires Android 4.3 or above, iOS 7.1 or above, Bluetooth 4.0 or above, Download APP "fitpro" from Apple Store or Google Play Intelligent monitoring of the sleep quality, Walk Tracker, Data Counting, Heartbeat.