Gas Charged Lift Supports are energy storage devices which create energy by compressing gas inside a cylinder. When closed, the energy is stored. When opened, the energy is released to raise hoods, trunks and hatches and hold them safely in an open position. To insure safe and effective operation, the lift support must match the specific application. After assembly, each AMS Gas Charged Lift Support is tested in four different positions during compression and extension to measure speed and force. Each lift is then subjected to two overload tests to assure structural integrity and safety. AMS Gas Charged Lift Supports are custom engineered and manufactured beyond industry standards to provide smoother operation and longer life. Lift supports should be replaced in pairs to ensure safe, reliable support of your application. If you have questions call our tech support at 1-800-528-6743