LifeTrak Zone R420 Adjustable Heart Rate Watch, Gray/Sport Red Stream and record continuous heart rate via chest belt (belt sold separately), or check your heart rate with the ECG accurate heart rate finger touch via push button Think long term. Review more than a year of data and detailed charts. Compatible with LifeTrak fit, Apple health & google fit Apps and valid integrated Get all day calorie burn stats for a more accurate picture of your progress. Automatically calculates calorie burn using heart rate readings and daily activity Conveniently see your progress and stats without pulling out your smartphone. Use the generously sized display and buttons for easy navigation Auto sleep and wake detection. Tracks sleep duration and quality to help you determine if you need to make adjustments to your sleep habits