If running is what you do to stay in shape, the Polar RS100 will give you valuable feedback that can help improve your fitness or lose those last few pounds. It combines all the heart rate features you need with the stopwatch youre used to. Track your average heart rate and time for each lap, so you can integrate heart rate easily into your fitness running program. The Polar OwnCal feature counts and displays your calorie expenditure during one or over several exercise sessions. Updates can easily be downloaded through the Polar UpLink Tool.