Valve cover grommet, also known as a positive crankcase ventilation grommet.
Dimensions: 0.486" ID x 1.071" OD x 1.248" Thickness
Fits the following Buick vehicles equipped with 260/307/350/403 c.i.d Oldsmobile engines:
Apollo 1975
Century 1977
Electra 1977-87
Electra (Estate Wagon sub-model) 1988-89
Estate Wagon 1977-83
LeSabre 1977-90
Regal 1977, 1986-87
Riviera 1977-85
Skylark 1975-77