Xiaomi Mi Band Smart Wristband Bracelet Fitness Wearable Tracker Waterproof IP67 MiBand Smartband for IOS 7.0 Android 4.4 Military-grade sensor 45+ day battery (depending on features enabled) Monitor your activity levels, track walking distance and calculate calories burned. Automatic sleep monitoring analyzes your sleep quality. Sync with the app to analyze your fitness and sleep activities to help you improve your lifestyle.