Abstract: The invention relates to a compressible-fluid device such as a gas spring, including a compression chamber (3) and a piston (4) that is movable in said chamber. It includes a safety member (21) disposed so as to be struck by the piston (4) in the event of the stroke of said piston being greater than a predetermined nominal stroke. The safety member (21) is arranged so as to cause the compression chamber (3) to be drained when said safety member is struck by the piston.