ROOP Fitness Tracker with Heart Rate Monitor Waterproof Fitness Tracker Touch Screen Activity Tracker Sleeping Monitor Pedometer Watch with Calling Number Display for IOS 7.0+ and Android 4.3+ (red) Heart rate measurement window below the heart rate bar chart, each measurement is shown as a pillar shape, click on the column can view when all heart rate value of measurements and graph heart rate upward sliding interface, for the last 7 days and 30 days all of the heart rate measurement data record Easy-to-read display, view the time of day and your stats right on your wrist with a gentle touch on the screen In sports wear bracelets, open heart rate Monitor measurement mode, can real-time monitoring the variation of heart rate in exercise, healthy, the highly effective movement Download the app from App Store or Google Play Store, this traker is a system, Wristband + Traker+ mobile app, that tracks how you sleep, move and eat so you can know yourself better, make smarter choices and feel your best, It's compatible with iPhone/iPad with IOS7.0+ system (but sometimes iPhone4 does not work reliably, iPhone 4S and later model works great) and Android phone/tablet with 4.3+ system