This watch means that you can track your heart rate for when you are exercising. It has many functions such as a Stopwatch, Clock, Date, Current Heart Rate, Max Heart Rate, Adjustable Limits & Visual Zone Alarms. The PC7 heart rate monitor is described as the optimum cardio control for sports & fitness. Heart rate monitored exercise leads to weight loss through fat burning. This is a great watch for any endurance athlete that may like to run on a night, run in completions & so on. ECG-exact 100 % water resistant Compatible to all cardio-instruments Changeable batteries Light & comfortable fit of the stretch band