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 included in this assortment come in M3-0.50 and M4-0.70 coarse thread sizes. Full assortments of #46030 contain sixteen (16) refills comprised of Hillman item numbers #4398 - #4400, #45329 - #45334, and #410817 - #410823.