You have to take into account the when you are training, either you are running, swimming, biking or on a treadmill, you are making great body movements. And when you do such activities, there is a need for a large display. Large display would enable you to read easily in arm s length your heart rate without the need of stopping for few seconds. When you use wristwatch heart rate monitor, it is no question that the data you would get are accurate. This would also eliminate the old problem of heart rate reading while moving. The wristwatch heart rate monitor would not require you to stop and check your heart rate that often disrupts the should be continuous workout and consistency of heart rate. The belt strap heart rate monitor and the strapless heart rate monitor both can accurately provide the user with accurate heart rate measurement which is impossible with manual method. The main advantage of the belt strap heart rate monitor on training is that the user can have an instant access on the status of the heart anytime he/she wishes to. Heart rate monitors come is different form but the most common is the belt chest heart rate monitor. The belt chest heart rate monitor however does not stand by itself. Since the belt chest contains sensor and a transmitter, and transmitters should have a receiver counterpart, the belt chest heart monitor needs a receiver in the form of the wristwatch. Now outdoor enthusiasts will never have to manually check their heart rate with these Polar heart rate monitors. For people who want to mange their weight with the use of Polar heart rate monitor, there are specific models designed for them. These are the WM42, WM41, WM21, and the Polar WM22. And if people who is not very adventurous but want to stay health, Polar has, the M31, M32 M61, M62, A5, A3, F5, F3, F2, and the F1. Both should fit to your body well and both should be able to work together by properly submitting data from the chest strap to the wrist display. Some are heart rate monitors are coded some are not. A good heart rate monitor is coded for it does not interfere or is not prone to interference to other monitors which could result to inaccurate readings.