About this item Accuracy Both Inside & Outside -Track your pace, distance and altitude with the integrated GPS. When you run indoors, Polar M430 tracks pace and distance from your wrist movements. Continuous Heart Rate Monitoring - Wrist-based technology gives you heart rate all day and night even underwater. No chest strap needed. Custom Running Metrics and Plans - Shows how your running performance is developing, training benefit, and recovery status. Get a personal, adaptive training plan that fits you and your goals. Activity/Sleep Tracking - Feedback on your daily, weekly and monthly activity, showing how your choices help you stay healthy. Polar Sleep Plus automatically records your important sleep metrics. Works with Your Favourite Apps - Your training and daily activity details are automatically sent and available to be used with Polar Flow, Strava, TrainingPeaks, Apple Health Kit, Google Fit and more.