Description: 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. Then bend the open tips to secure them in place. Depending on the application, various sizes and finishes are available. Feature: 1. The specialty lock ensures a durable and tight-lasting hold-on. 2. Insert the cotter pins into the holes of certain types of fastener systems to hold them in place. 3. Once inserted through the hole, the two prongs at the opposite end can be separated and bent outward to lock the pin. 4. Cotter pins are most frequently used to secure clevis pins, castle nuts, bolts transmission drag chain and pin shaft to ensure normal operation of mechanics. 5. The bulbous end prevents the pin from being pulled through the hole so it is important to select a pin that has a diameter measurement larger than the hole diameter in the fastener you are working with.