Water resistant up to 50m.Features time (12/24 hour setting), alarm plus hourly charm and out-of zone alarm.Programs your heart rate zone.Patented One-Touch Technology displays heart-rate in seconds with a single touch.3 beat speed sensor.ECG accurate heart-rate reading.Measures calories burned.No chest belt required.Suitable for walking, running or the gym.Large digital display, backlight, chronograph and countdown timer.