VW 1600 Based Type 1 And 2 Fan Shroud Air Duct Plugs. Fan shroud air duct caps are used when the fresh air hoses for the heater boxes are not in use. These are to keep all the air flowing down to the engine so air is not lost through the open holes. Available in 2 sizes, 1 size for O.E. fan shrouds and 1 size for EMPI and other aftermarket fan shrouds. Includes mounting screws. Sold in pairs.