Bearings units combine a double-sealed ball bearing with various types of bearing housing. These are optimal units
which are self-aligning at the spherical fitting surface of the bearing and housing.

The outer surface of the bearing and the internal surface of the housing are spherical, so that the unit is self-aligning.
The inside construction of the ball bearing for the unit is such that steel balls and retainers are of the same type as in
deep groove ball bearing.