The Polar F55 is the newest watch in the Polar line of heart rate monitor watches. It is the successor to the F11 with an array of upgraded features. The F55 is a complete heart rate monitor system that includes continuous monitoring of your heart rate during your exercise period and includes target zones with audible alarms when you step outside the preset zones. The most notable difference between the F55 and F11 is the ability of the F55 to connect with non-polar devices using a standard infrared port. The other differences include 2  main Polar presets: 1. The Polar OwnRelax, in which the wearer relaxes for a 5 minute period and the watch determines how relaxed your body is. 2. The Polar Body Workout, which provides strength training suggestions, reps and sets.