Bronze Series DS54 is a Dura Shock Hand Aneroid Sphygmomanometer. It provides a shock resistant for accuracy and maintain accurate blood pressure readings at a lower lifetime cost with gear-free DuraShock™ technology, the first major innovation in aneroid technology in nearly 100 years. The DS54 provides a traditional thumbscrew-style air release valve. Also, it gives a 5-Year calibration warranty.