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 come in 3/8" & 7/16" diameters and range from 2" to 3" in length. Full assortments of #45978 contain six (6) refills comprised of Hillman item numbers #408055 - #408057, #408060, #408061, and #408063.