The Omron® 7 Series Wrist Blood Pressure Monitor offers convenience, portability and accuracy. With Heart Guide Technology, the device automatically activates when a patient's wrist is at heart level to ensure an accurate reading. It also detects irregular heartbeats while the patient's blood pressure is being measured. The attached cuff fits wrist sizes 5.3" to 8.5" in circumference. The monitor comes with 2 "AAA" batteries.