The Amazfit Bip S is designed to be more powerful than the previous generation, thanks to the revolutionary design of the watch materials and manufacturing process, while remaining ultra-lightweight. With only 31 grams with the watch band, the watch is very comfortable to wear while doing sport or sleeping. Product Name: Amazfit Bip S Input Voltage: 5V, 500 mA(Max) Wireless Connectivity: Bluetooth 5.0 Model Name: A1821 Compatible with: Android 5.0, iOS 10.0 or above Package Record-breaking battery life: Up to 40 days on a basic usage scenario and up to 15 days on a typical usage scenario Always-on display: 1.28 transflective color display with Corning Gorilla 3 tempered glass + Anti-fingerprint coating Smart features: Notifications, remote music control, alarm clock, sedentary reminders, weather forecast, and more. Multisport tracking: Track your runs, cycling and more with mapped routes, detailed stats and heart rate zones. Latest technology: Built-in GPS + GLONASS, 3-axis accelerometer, BioTracker PPG optical heart rate sensor, barometer and compass.