You are buying ten (10) NEW fasteners. They are 5/16-18 zinc plated nuts with mastic sealer that can be used on Buick, Cadillac, Chevrolet, Oldsmobile, Pontiac & GMC cars & trucks. They have a 13/16" diameter flange and a 1/2" hex. These nuts are used on a threaded stud. inkfrog terapeak inkFrog Analytics