Now check your heart rate quickly and easily at any time. Simply press the two buttons on the face of the HRM watch and it reads your heart rate in 4-5 seconds. Also, counts calories consumed during the day against a target to let you know when you reach your daily calorie quota. Full-featured sports watch with time, date, chronograph, alarm and back light. Petite size fits wrists up to 6.75”; large size fits wrists over 6.75”.