Most models are waterproof enough for swimming, but not diving. Polar transmitter - worn at midriff. Less expensive are hand-held pulsemeters, which may also incorporate some features such as stopwatch. There are many features in the monitors, which determine the price differences. Since you wear it like a watch, it is nice to have it be a watch, too, so you don't have to wear another watch when on your workout.
Some models allow multiple zones to be programmed.
More fun for those who are concentrating on going fast and training for races. This comes in handy for several kinds of workouts. Get instant satisfaction with this calculation of how much you have burned. Great if you exercise at night. Choosing the Right Heart Rate Monitor Heartmind Questionnaire Go through this online questionnaire to lead you to the right model.