Spherical plain bearings are made up of an inner ring and an outer ring with sphered outside and inside surfaces. They enable angular rotation about a central point in two directions and sustain a rotating shaft in the bore of the inner ring that has to move not only rotationally, but also at an angle. Spherical plain bearings are used in all those applications, where rotational motion must be permitted to modify the alignment of its rotation axis. Rod end bearings are precision mechanical articulating joints, that consist of an eye-shaped head where a spherical plain bearing is assembled.