Measurable arm circumference: Approx. 22cm-32cm. Multi-functional display: Displays the date, time, battery life, and both kPa and mmHg for blood pressure. Accuracy: Pressure +/- 3mmHg and pulse rate +/- 5%. Digital health monitor: Get a 4-in-1 blood pressure monitor. Safety features: Device will exhaust quickly if the pressure is higher than 300mmHg, and will shut down after one minute of no use.