Welch Allyn DuraShock Technology: More-accurate blood pressure readings and lower lifetime ownership cost due to award-winning design that is both gear-free and super shock-resistant. Welch Allyn's Shock Resistant Classic line of aneroid sphygmomanometers featuring gear-free, super shock-resistant DuraShock technology offer practical benefits compared to traditional sphygmomanometers with gears. This is especially true in busy medical environments where instruments may be handled roughly or dropped. With DuraShock technology, Welch Allyn sphygmomanometers will remain in calibration longer, providing more accurate readings than traditional sphygmomanometers with gears. Shock Resistant Classic gauges will not need to be replaced as often as traditional gauges with gears, providing lower lifetime ownership cost.