Ball bearing units are ready-to-install ball bearing units which are usually screwed in an upright position on a mounting surface.

The housings are designed either in one piece (to support low loads) with a special ball bearing or in two pieces (to support higher loads) with standard self-aligning ball bearings or spherical roller bearings.

On account of the straightforward design and respectively low manufacturing costs, single-piece bearing units are increasingly being used.
Misalignment or bending of shafts by up to 5° can be compensated by the convex design of the ball bearing outer race. This moves within the ball-shaped bearing seat (angular movement) in the housing and also prevents edge pressing between balls and raceway.