Battery capacity: 45mAh Standby time: 10 days Batteries Type: Lithium Polymer Input Current: 25mA (TYP) Input voltage: DC5.0V Waterproof: IP67 Heart rate sensor: Optical heart rate sensor Adjustable length: 157~205mm Measuring method: photoelectric volume pulse wave plethysmography (PPG) Bluetooth chip: Dialog top Bluetooth chip (Bluetooth 4.0) Sensor: ADI military gravity sensor App: Mi Fit Language: English, Chinese, Russian, Spanish, Polish, Portuguese, Turkish, French, German Device Requirements: Android 4.4 and above versions, and supports Bluetooth 4.0 for Android smartphones; Adapter For Apple iOS 7.0 or later and For iPhone 4s / 5 / 5c / 5s / 6/6 Plus / 6s / 6s Plus. Bracelet unlock Supported models: Xiaomi 2 / 2S / 2A, Xiaomi 3, 4 Xiaomi , Xiaomi Note, Xiaomi 4C, Redmi 1S, Redmi 2 / 2A, Redmi Note, Redmi Note2 (need to upgrade to MIUI6 and above systems), Bluetooth 4.0 Android 5.0 over the phone. Packing List: mi band 1S chip, black wrist strap, charger, user manual.