Batteries, automatic blood pressure cuff arm, and storage bag included. The blood pressure monitor has an arrhythmia detector that will flash on the display if an irregular heart rate is detected, ensuring accurate low or high blood pressure readings. The technology in this blood pressure monitor meets the highest clinical standards. When used correctly, this BP monitor will provide readings comparable to a doctor's office. It detects movements that could interfere with a blood pressure reading, and a symbol will display when you are sufficiently at rest. For best results, rest for 5 minutes before a reading. The automatic BP cuff comes with a position guide and fits standard to large upper arms of 9" to 17". Simply position the cuff, press the power button to turn on, and press again to measure.