Get fit and stay healthy with the Mi Band 4 Activity Tracker from Xiaomi. Working in conjunction with your Android or iOS smartphone, this fitness tracker provides you with a variety of fitness and health tracking options, as well as practical functionality, such as Find My Phone, Phone Unlock, and music playback controls. When it comes to health, the Mi Band 4 can monitor your sleep and give 24/7 heart rate monitoring with the built-in optical heart rate sensor. Both basic activities and specific workouts/exercises can be monitored and tracked. Basic activities, such as counting steps, distance traveled, and calories burned. The workout modes the Mi Band 4 covers include treadmill, outdoor running, cycling, walking, swimming, and more. Viewing your tracking data is easy thanks to the 0.95" color AMOLED display. A built-in 135mAh battery lets you do all of this for up to 20 days before requiring a recharge.