A flexible locking gas spring has gas on both sides of the piston. Gas is compressible so if sufficient force is applied to the rod when it is in its locked state, either in tension or compression, the gas will compress and the rod will move a few millimetres from its locked position. When the force is removed the rod will return to its original position, while remaining locked, giving the characteristic flexing movement.

A small quantity of oil is inserted into the spring so that in its normal rod down position, the seal is lubricated for maximum life. Other orientations are possible by the addition of an oil chamber.