As a chest mounted ECG/EKG, the TRACKR HEART RATE sensor is best installed centered at the base of the sternum, just below the pectoral muscles.
To ensure the most accurate readings, in cold or particularly dry environments, slightly moisten the skin contact pads on the inside of the strap, and then place the unit directly on the skin. In order to prevent loss of contact, avoid putting any clothing between the strap and your body.