You are buying thirty (30) NEW fasteners. This listing is for (15 pcs) 10-24 x1/2” and (15pcs) 10-24 x 3/8” grille rivet screws.  They are zinc plated steel grille rivet screws with stainless steel Keps nuts for  1955-1957 Chevy Bel air , 1958 - 1968 Chevy Bel air , Biscayne and Impala  1964-1969 Chevy Chevelle and El Camino and 1962-1967 Chevy Nova. These threaded fasteners are 10-24 x 1/2" and 10-24 x 3/8” long and have a  .375" (3/8) diameter domed head.

Please not these are not OEM style aluminum rivets.