The MDF® Calibra® Sphygmomanometer is stress-tested 3,000 times and calibrated five times to bring you one of the most durable, accurate and dependable pocket aneroid sphygmomanometers on the market. The Calibra® is ideal for medical professionals and home users with its simplicity and accuracy of +/- 3mmHg (industry standard) without the use of a pin stop. Backed by our Lifetime Calibration Warranty.