NJ series bearings have ribs on both sides of the outer ring, and ribs on one side of the inner ring. Can withstand a certain amount of unidirectional axial load.

NUP type bearings have ribs on both sides of the outer ring, a (fixed) single rib on one side of the inner ring, and a separable flat rib on the other side. Can withstand a certain amount of bidirectional axial load.

The NU type bearing has ribs on both sides of the outer ring and no ribs on the inner ring. It is also possible to allow displacement of the shaft relative to the bearing housing in both axial directions. Therefore, this type of structure is suitable for use as a loose end bearing.

The NU type bearing has ribs on both sides of the outer ring and no ribs on the inner ring. It is also possible to allow displacement of the shaft relative to the bearing housing in both axial directions. Therefore, this type of structure is suitable for use as a loose end bearing.