SUBA Heart Rate Monitor, Wirless Fitness Tracker, Smart Wristband with Multi-Functions Activity Tracker for Android and iOS HEART RATE MONITOR WRISTBAND: Managing heart rate COMPATIBILITY: requires Android 4.4 or above, iOS 7.1 or above, Bluetooth 4.0 or above. download APP "Veryfit 2.0" from Apple Store or Google Play WIRELESS FITNESS TRACKER: Transmits Heart Rate To Compatible Device MULTI-FUNCTIONS: Track steps, distance, calories burned and active minutes WATERPROOF: TPU material waterproof, not afraid of washing hands/ doing housework/ walking under rain.