This Blood Pressure unit employs the oscillometric method for the measurement of blood pressure and heart rate. It inflates manually and 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 (9 to 12 1/2"). the The unit stores the 30 most recent measurements for comparison. It uses 4 AA batteries (included) and comes complete with instructions and a carrying case.