This bearing unit is a combination of a radial ball bearing, seal, and a housing of high-grade cast iron, which comes in various shapes. The outer surface of the bearing and the internal surface of the housing are spherical, so that the unit is self-aligning. Ductile cast iron housings are lighter and will perform well in harsh environments. Like all housed units, they are designed defining the allowable load limit, insert bearing life, and maximum allowable breaking strength.