External Snap Rings are used to secure a shaft into a housing. They fit into grooves in the side of the shaft for a snug fit and often are slightly recessed into the side of the housing the shaft is protruding from. All of our External Snap Rings are made of spring steel with Black Oxide Coating. All of our External Snap Rings are imported from Chinese Manufacturers and then conveniently packaged for little waste. To determine the External Snap Ring you need, measure the shaft and then order the same size snap ring. External Snap Ring are sized to the shaft and not to the the groove in the shaft. An External Snap Ring fits right when it snaps into the groove and then floats freely or moves with just a little friction and is not distorted. It should be impossible to pull the replacement External Snap Ring off the shaft without the use of Snap Ring Pliers or by prying underneath with a sharp object. You will likely need a Snap Ring Tool to install a snap ring but you can often work a replacement snap ring onto the shaft from the end with a pair of needle nose pliers and a small screwdriver. External Snap Rings can be easily damaged when installed because they have to be stretched over the shaft during installation.