Activity tracking 3-axis accelerometer and 3-axis gyroscope. 24/7 Heart rate monitoring Safeguard your health at all times. Alerts you when your heart rate is too high. Idle alerts Stay active as you get reminders to get up and get moving. Recognises 5 different swim styles and records 12 data sets including swimming pace and stroke count. Battle ropes Whether you're doing high-speed battle rope training or an aerobic battle rope workout, Mi Smart Band 4 will track your heart rate, calories burned and more. Power walking 5 core data sets - Helps you improve power walking efficiency. Smarter Music Controls Workout to your favourite music. Change the song, increase and decrease the volume with music control. Unlimited Watch Faces Comes with pre-installed watch faces and an option to choose pictures from your gallery. Enhanced Mi Fit Interface The interface allows you to track vital metrics and customise your workout to suit your needs.