The WDR Wiper is similar to WDD Wiper Seals, but in TRIATHANE® (Poly-Urethane) material and also with 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.