A shock absorber is a mechanical device designed to smooth out or damp a sudden shock impulse and dissipate kinetic energy. It is analogous to a resistor in an electric RLC circuit. It is used to absorb or dissipate energy. Pneumatic and hydraulic shock absorbers commonly take the form of a cylinder with a sliding piston inside. Shock absorbers are an important part of automobile and motorcycle suspensions, aircraft landing gear, and the supports for many industrial machines.

The shock isolator consists of lightweight cylinder containing compressed air and a piston, which is fully extended at steady state. In a shock isolator a piston is movably mounted within a compressible solid chamber formed within a housing. The compressible solid material to be extracted through said first passages during an extension of the piston, the compressible solid material to be extracted also through the second passages during retraction of the piston. A ring surrounding the piston, the ring to close off the second passages during extension of the piston, during retraction of the piston the ring to move to permit the compressible solid material to flow therethrough.