1.Method of measurement: oscillometric method 2.the recorder uses aneroid battery. Beeps and screen message will notify its user when voltage is below 4.3V. 3.Range of measurement: 1.3kPa~40kPa (10mmHg~300mmHg), Precision:+-0.4kPa (+-3mmHg) 4.The recorder can also measure heart rate. 5.The pressure sensors of the recorder can auto-clear to zero. 6.The recorder has a venting speed no more than 0.67kPa/s during testing, and automatically deflates afterwards.