BodyMedia LINK Body Monitoring Armband Track your activity and calorie burn like the contestants on The Biggest Loser and endorsed by health and wellness expert Jillian Michaels The BodyMedia system automatically tracks your calories around the clock helping you to lose weight and even improve your weight loss by 3X proven in group trials Provides most accurate calorie burn measurement in market (data available on BodyMedia.com) Bluetooth-enabled to work with BodyMedia iPhone and Andoid apps so you can see your data in real-time and upload wirelessly Food logging also available with app Works with MyFitnessPal, Runkeeper, Sparkpeople and more