Polar RS400 Running Series Heart Rate Monitor。For endurance athletes and runners who rely on systematic training - Helps avoid over or under training by aiding you to train at the right intensity - Measures detailed information about your performance - The Polar Fitness test measures your aerobic fitness at rest and tells you your progress - Comes with Polar ProTrainer 5 software for analysing, planning and keeping a training diary ZonePointer - Makes it easy to stay in your target zone. A visible and moving symbol on the display of your Polar product indicating that you are inside the pre-set target zone. ZoneLock - Simply the easiest way to set a target zone. You can activate a target zone with a press of a button during your run. You can also deactivate the zone alarm just as easily – by pressing a button. Event Countdown Timer - Set your goal and stay motivated. Keeps your motivation high by showing how many days are left before your next running event (e.g. Berlin 23 days). Interval trainer (HR, pace, distance) guided workouts - Create your personal multizone workouts with heart rate/speed/distance and timing guidance. Allows you to create and name your own favorite workouts based on time, heart rate, speed/pace or distance guidance with up to three linked timers or distances and up to three target zones. Polar Fitness Test with OwnIndex - Measures your fitness level in 5 minutes. A fitness test that measures your aerobic/cardiovascular fitness at rest in just five minutes.