Valve cover to air cleaner vent pipe. Mounts in grommets on the valve cover breather and air cleaner. 

1969 Oldsmobile all  models with 350 C.I. except Cutlass models

1969 Oldsmobile models with 400 and 455 V8

1970-72 Oldsmobile Cutlass models with 455 V8

1970-72 Oldsmobile Delta 88 with 350 C.I. engine

1973 Oldsmobile all models with 350 C.I. engine

1974 Oldsmobile all Cutlass, Delta 88, Delta 88 Royale, with 350 C.I. engine

1975-89 Oldsmobile various models