This is the wrist blood pressure monitor that changes color when it detects an out-of-range reading, alerting you of potential problems in the simplest possible terms. The monitor uses the oscillometric method of blood pressure measurement that is accurate to within +/-3mmHg, and clinically proven to provide precise readings for hypertension and arrhythmia. Readings that fall within the systolic or diastolic limits you've pre-entered are displayed in blue; readings that fall outside the targets cause the monitor's screen to turn red. The monitor's LCD panel shows blood pressure readings in large numerals, as well as heart rate. The unit's internal memory stores 90 readings. Simple to operate and comfortable to wear, the monitor's cuff fits 5 1/4" to 7 3/4" circumference wrists and is held securely by a hook-and-loop fastener. Comes in a protective travel case. Includes 2 AAA batteries. 3" L x 3 1/4" W x 1 1/4" H. (6 oz.)