The function of the Aston Seals SMA wiper ring is to prevent introduction of dust, dirt and foreign matter into the system. This is achieved by a special wiper lip which produces a very effective cleaning action, prevents the development of scores, protects the guiding parts and extends the service life of the axial moving rod seals. A flush fitting with the outside diameter of the metal cage prevents moisture from entering
the groove. The material used to produce the wiper element is a nitril rubber with hardness 90° ShA that ensures a good wear-resistance in case of dry run and an extended service life.