A metal washer bonded to rubber, bonded washers (aka Dowty washers) are used to prevent leakage of media through fasteners of hydraulic fittings, pipe join flanges and valve bodies. A bonded washer consists of a flat metal ring with rubber bonded to the internal diameter that is wider than the metal washer. As the bolt or fitting is tightened, it compresses the rubber seal element until fully tightened upon the metal ring creating an efficient high pressure seal.