The Xiaomi Watch S4 is a premium smartwatch with a lightweight aluminum alloy frame and a stunning 1.43-inch circular AMOLED display (466 × 466 pixels, 326 PPI) with 60Hz refresh rate and HBM 1500 nits brightness.
It comes equipped with a full range of sensors including heart rate, SpO₂, accelerometer, gyroscope, ambient light, compass, barometer, and hall sensor.

With a 486mAh battery, it offers up to 15 days of usage and charges via 2-pin magnetic dock.
Features include Bluetooth calling, 5ATM water resistance, built-in GNSS (GPS, Galileo, Glonass, BeiDou, QZSS), dual microphones, and NFC support.
Runs on Xiaomi HyperOS 2 and supports smartphones running Android 8.0+ or iOS 14.0+.