I bought this heart monitor because it gives pulse readings without a bulky transmitter wrapped around your chest. In my experience, it gives accurate pulse readings on pressing the button for 5 or 6 seconds AT REST ONLY. It did not give me accurate readings while jogging, and it took longer to get any reading(about 15-20 seconds) while in motion. I also have a heart monitor watch with a transmitter, and that gives me continuous readings while jogging. My conclusion is you need a transmitter if you want accurate pulse readings while in motion. For readings at rest, this watch is just fine.