As the name implies, these parts make your spherical rod end installation safer. These parts perform two critical functions: First if the rod end were to fail, the end would not be able to slip over the retainer bolt. Second, the tapered profile allows the spherical to travel through an extended range without the limitation posed by a simple flat washer. These parts come in sizes that can be used in small linkages and up to large suspension assemblies. The washers are offered in Aluminum, Stainless and Alloy (4130 steel).