Mi band 4 is a fitness, sleep, and heart rate tracker. Extremely affordable yet with rich features and high quality, its slim form factor, light weight (22.1g), soft material, and 50-meter water-resistance allow the user to comfortably wear it 24/7. A full-color AMOLED touch display is added to Mi Band 4 without changing the design language and the iconic pill shape outline of its predecessor. The display offers rich information as well as a wide selection of watch faces.