Polar Men's FT4 Heart Rate Monitor (Orange/Black) Heart rate monitor shows fitness progress based on heart rate Wrist unit displays calories burned and includes comfortable textile transmitter plus coded heart rate transmission to avoid cross-talk Automatic age-based target zone automatically determines heart rate target zone limits according to age-based maximum heart rate Polar OwnCal calculates number of calories burned during training, during individual sessions and cumulatively over time Polar OwnCode (5kHz) coded heart rate transmission automatically locks in code to transmit heart rate to training computer, preventing interference from other training computers