Make fitness fun and efficient with Polar's F6. It accurately measures your heart rate so you can pick the perfect workout and track your progress. You'll know how hard to push it, too, because the F6 checks your body's daily condition and adjusts accordingly. Plus, Polar's OwnZone automatically determines target heart-rate zones and the OwnCal feature counts calories and fat burned. You won't believe how satisfying it is to see your progress on the F6!