This Wrist Model Digital Blood Pressure Monitor which uses the oscillometric method for measurement of blood pressure and heart rate, is a single wrist-mounted unit. the cuff wraps around the wrist and inflates automatically. The cuff will accommodate a wrist circumference range of approximately 13 to 20 centimetres (5 to 8 inches). The unit stores the 30 most recent measurements which are displayed on an LCD readout. It uses 2 AAA batteries (included) and comes complete with instructions and a carrying case.