In pneumatic cylinders, cushioning seals are part of a design that provides for controlled final position retardation. Up on approaching the final position, a tapered sleeve, firmly located on the piston rod, progressively closes off the open passage toward the line connection of the cylinder. In this phase of motion, the defluent medium is led via a, usually adjustable, needle valve, the adjustment of which controls the degree of stroke movement retardation. During reverse operation, the cushioning seal designs provide a non-return valve functionality and ensure free flow. Parker offers robust seal profiles, suitable for the harshest operating conditions and showing extreme wear and high-temperature resistance.