The power of heart rate on your wrist. Let your heart be your guide with these two Charge HRs and correspondong scale. Monitor heart rate automatically and continuously right on your wrist to accurately track calorie burn, maintain workout intensity, maximize training and optimize health. The Aria scale tracks not just your weight, but your body fat percentage and BMI, too. Painting a picture of your long-term progress, it wirelessly syncs your stats with online graph and mobile tools that help you stay motivated and on track. www.fitbit.com