Mio OOO51USCLS Classic Select Petite Strapless Heart Rate Watch Wristwatch-style HRM provides accurate heart rate without a chest strap; fits wrists smaller than 6-3/4 inches Measures your heart rate by applying two fingers to the watch for a matter of seconds Personalized percent of maximum heart rate display, counts calories burned during exercise Tracks calories consumed against a daily calorie target and displays daily calorie balance Interchangeable watch ban