Rod ends (sometimes called heim joints) are very common on aftermarket suspension links. They come in many grades with the best typically having heat-treated chromoly or stainless steel bodies, plus Teflon or similar liners between the body race and the spherical ball inside. The liner serves to lubricate and prolong the life of the joint, especially under off-road use. Over time, however, even the highest quality joints will start to push the liner out of the joint as shown here and start to develop looseness. Once this occurs, they need to be replaced. When significant angular flex is needed, misalignment spacers can be added to a rod end, at the expense of a decrease in mount bolt diameter.