Xiaomi Mi Smart Band 4 Smart Band Activity Tracker Brand: Xiaomi Notification functions: Incoming call notifications, email notifications, Line notifications, etc. Settings on the smart band itself are also displayed in Japanese. Sensors: Heart rate sensor, gyroscope sensor, acceleration sensor, step count, heart rate measurement, calorie consumption, sleep detection, waterproof and dustproof functions, Bluetooth connection I am selling this because I have replaced it. The battery life lasted for more than 10 days from a full charge, but this depends on usage, so I cannot guarantee it. The black silicone band is unused. The white silicone band and the nylon band have some signs of use. The white color is starlight (cream white). The USB charger is a third-party product that allows charging without removing the band. You need the Zepp Life app on your smartphone to use it. You can change the watch face design in the app.