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.