"This is an item I first seen used to hold bait doors closed on cage traps. They also work great for connecting traps to drowning rods or cables. You can open them with a gloved hand and close them on a link of chain, at whatever length you choose. On my own trapline, I've trapped 100's of raccoons with this setup (on drowning rigs) and have not had any open up on me. The connecting eye swivels also."- Gerald Schmitt. Length is 2 3/4".