Polar RS400 Heart Rate Monitor Watch  Product Description: The Polar RS400 Heart Rate Monitor is designed for the active endurance athlete who wants to improve their performance by planning, monitoring, and analyzing training data. The heart rate monitor features such innovations as OwnCal® to count and display calorie expenditure, the Fitness Test with Own Index® to measure your fitness level in 5 minutes and high-tech watch features like alarms and dual time zone.