Our fuel Injector Rail Plug for diesel vehicles keep high pressure oil in the oil rails which power the fuel injectors. All our Fuel Injector Rail Plugs are made from high quality materials for durability. Product Features:O-Rings require replacement when going into the Oil Galley for ServiceLeaking high pressure oil tubes cause the engine to run poorly or not at allDirect fit replacementHigh pressure oil stand pipe also available, sold seperately