Water resistant (IP67)30-day standby powerSleep-cycle smart alarmFitness monitor sleep trackerRunning MIUI Android 4.4 and aboveUnlock your Mi phone without a passwordSpecifications:Input Voltage : DC 5.0VBattery Capacity : 41mAhCell Type : Lithium PolymerInput Current : 25mAh (TYP)Alloy Body Dimension : 36*14*9 mmAlloy Body Shell Material : PolycarbonateWrist Strap Material : DowCorning TPSiVMetal Face Material : Magnesium Aluminum AlloyLED Notification Light : Blue, Green, Red, OrangeAdjustable Wrist Strap Length : 157mm ~ 205mmWeight: 5.0gColor: blackCompatible with Xiaomi Mi4 / Redmi Note 4G LTE/ Xiaomi Mi3 featuring Bluetooth 4.0Record your movement data throughout the day.When you enter the sleep state, Xiaomi band began to records.Automatic sleep monitoring, it knows that if you sleep well. And keep track of your sleep time, from it, you can learn more about the quality about your sleep.Smart vibration alarm, simulate the state of nature to wake.Mobile phone calls reminding function.With your MI4, MI3 or Hongmi Note 4G Version, you can find so many funny things from it.30 days duration, waterproof, Automatic looking for itself, Unlock your phone without a password... So many greatful function, it is just for you.