Cotter pins are used to secure two items together with the use of a common hole. Place the cotter pin in the hole. The bulbous head stops the pin from moving all the way through. To secure in place, bend the open tips using pliers. This assortment features zinc-plated steel cotter pin variants sized 1/16" thru 1/4" in eye diameter. Full assortments of #1359 contain sixteen (16) refills comprised of Hillman item numbers #1360 - #1375.