Xiaomi Mi Band 4 Smart Miband watch

Check your heart rate in real time to make sure you get the best workout as you climb mountain roads or dash around the city.
5 ATM water resistant up to 50m, Recognizes 5 different swim sles
Sport Functions- 6 workout modes: Treadmill, exercise, outdoor running, cycling, walking, pool swimming; Count steps, distance, and calories burned
Health monitoring- Workout completion notifications, goal setting, sleep monitoring, heart rate monitoring, all-day heart rate checking, resting heart rate, heart rate chart, idle alertAPP Notifications- Alarm, proximity sensor, pre-set watch face, customizable watch face, lock screen, timer, stopwatch, phone alarm and notifications, incoming calls, message notifications, calendar notifications, app notifications,
Touch Display- Find my phone, phone unlock, event notification, night mode, Do not disturb mode (works even without phone), music controls on band, Bluetooth broadcasting, battery level display, different ways to wear, OTA updates

Long Battery Life- A single charge lasts up to 20 days.