The Omron 637 Wrist Blood Pressure Monitor with A.P.S. (Advanced Positioning Sensor) provides the most accurate readings of any wrist-style blood pressure monitor!. Just slip it on your wrist, press START and let the APS system guide the cuff to the proper placement at heart level. This is critically important for a wrist monitor - you MUST have the monitor at heart level to ensure the most accurate reading. Now it's easy! It's watch-like styling means you no longer have to take off your shirt or struggle to roll your sleeves up past your elbow to get a blood pressure reading. The HEM-637 Wrist Blood Pressure Monitor is completely automatic - just touch one button and it will automatically inflate, ensure correct cuff placement, quickly and accurately get your blood pressure and pulse rate and displays them on the large panel! And a huge memory records your last 90 measurements for you, making keeping track of your history simple. It operates on just 2 'AA' batteries, which are included for you. The HEM-637 even comes with a deluxe protective case. "Intellisense" technology used by the 637 Blood Pressure Monitor means that it inflates the cuff to the ideal level with each use. The sensors quickly stop the cuff's inflation to keep it comfortable - no matter what size your wrist is. No adjustments are required by the user to select an inflation level. This is especially important for hypertensive users and for people with certain arrhythmia or heart disorders, because their blood pressure is likely to fluctuate. The advantage is Personalized Inflation for maximum comfort. This may be one of the most comfortable and accurate blood pressure readings you will ever have!