High blood pressure (hypertension) affects more than 50 million people. Since there are often no warning signs or symptoms associated with it, everyone is a risk. That's why its so important to measure blood pressure regularly. If its high, steps can be taken to lower it. Just as important, if blood pressure is normal, steps can be taken to keep it that way. The Welch Allyn Home Blood Pressure System provides accurate, reliable oscillometric measurement. Powered by 4 standard AA batteries (not included) and an optional AC adapter. AAMI Standard: 18.104.22.168 of SP10. Cuff Pressure: 0 to 300mm Hg. Pulse Display: 40 to 150 beats per minute. Standard Cuff Size: 22 to 30cm. Large Cuff Size: 30 to 38cm.