IFit Link Activity Tracker 4 LED indicator lights- quick visuals to assess currently activity Auto-activity detection- automatically detects when you are walking, running, cycling, and sleeping Ble heart RATE Compatible- Connect with ble heart RATE monitor for more accurate calorie burn Adjustable textured band, 3-axis accelerometer, vibration notifications, 2 separate band sizes included (s+m or l+xl), automatic mode change Wireless sync with ble technology, ble updatable in field, connects to iFit, android and iOS mobile Apps available