An assortment of heat-treated automotive studs from The Hillman Group. Automotive studs are a headless bolt that is threaded at both ends with the center portion remaining unthreaded. They are used to insert one end into the head or block and then insert a nut or washer on the other end for applications such as bolting the exhaust manifold to the head. Variants included in this assortment range from 3/8 to 1-3/4 in USS thread size and from 5/8 to 1-7/8 in SAE thread size. Full assortment contains 12 refills comprised of Hillman item numbers #2766 to #2777.