Vktech&reg; OLED Bluetooth 4.0 Health Bracelet Wristband Fitness Sleep Activity Tracker Tracks steps, distance, calories burned and active minutes Stylish and durable, Smooth operation, OLED screen Sync only for IOS, Android 4.3 and above, NOT compatible with system below Android 4.3 Material: Environmental silicone Main functions: Pedometer, Distance course, Stopwatch, Time, Date, Week, Stopwatch, Sleep monitoring, Calorie burns