An assortment of stainless steel socket-head cap screws from Hillman. Socket-head cap screws carry a recessed internal socket drive to add strength. They are commonly used on machine parts, manufacturing equipment, and other mechanical applications. Variants in this assortment feature a coarse 5/16"-18 thread size. Full assortments of #43174 contain nine (9) refills comprised of Hillman item numbers #3259 - #3264 and #43175 - #43177.