This Blood Pressure unit employs the oscillometric method for the measurement of blood pressure and heart rate. It inflates automatically and gradually deflates automatically, registering systolic, diastolic and pulse measurements on a large LCD display. The cuff will accommodate an upper arm circumference range of approximately 23 to 32 cm or 9 to 12 ½ “. The unit stores the 30 most recent measurements for comparison. It uses 4 “AA” batteries (included) and comes with complete instructions and a carrying case.