The WED Wiper is similar to WDD style Wiper Seals, but in TRIATHANE® (Poly-Urethane) compound and diff erent groove dimensions, mostly suggested to be used in conjunction with a back pumping Primary Seal/ Secondary Seal, like TRITILT® (RSS style) Seal. The inner lip holds the fi lm of oil within the system without being leaked out and the outer lip shall prevent any dust particles entering the system.