An assortment of button-head socket cap screws from Hillman. Socket 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 range from #10-24 to 5/16"-18 in coarse thread size. Full assortments of #43559 contain sixteen (16) refills comprised of Hillman item numbers #3877 - #3880, #3883 - #3887 and #43560 - #43566.