Brass screw in plug for select Autolite distributor vacuum advance units from 1968-71, typically the banded single advance units factory installed. Solid brass, originals were not, we believe that they were cadmium plated. Solid plug, should be hollow, with a 3/4 inch hex head. Works as it should. Fits most all vacuum advance that have a plug in the end as shown.
*Note, when removing the old plug, there is a spring and washer inside.