This is the automatic wrist blood pressure monitor that takes readings with precision considered "very accurate" by The European Society of Hypertension standards. During in-use trials conducted by The Hammacher Schlemmer Institute, it deviated only 5.92% from measurements taken by a registered nurse using a stethoscope and sphygmomanometer, far superior to lesser models that varied by as much as 23.57%. The monitor uses the oscillometric method of blood pressure measurement, clinically proven to provide accurate readings for hypertension and arrhythmia, and takes three consecutive measurements separated by one-minute intervals, providing an average. It measures blood pressure at the touch of a button and automatically inflates around the wrist to the optimal level, causing minimal discomfort. Accommodates 5 1/4" to 8 1/2" wrists, stores 60 readings, and has a hard plastic case. Includes two AAA batteries. 2 1/4" H x 3" W x 1 3/4" L. (4 1/4 oz.)