The Hillman Group 43715 3/16 x 2-1/2-Inch Stainless Steel Cotter Pin, Stainless Steel, 6-Pack A cotter pin secures two items with the use of a common hole Place the cotter pin in the hole, the bulbous head will stop the pin from moving all the way through, bend the open tips to secure in place One prong of the cotter pin is extended for easy insertion