Four rows CRB is installed on roll neck with interference fit especially high rolling speed mill. This bearing geometry allows to be used on bigger roll neck diameter for same roll diameter. It has high radial load capability because of more rollers filling. Four rows CRB only take radial force, so always going together with DGBB or ACBB or radial/thrust TRB, the latter one take axial load.

Shaft can move axially again housing within certain limit. Four rows CRB offer couple options considering application and maintenance. All options difference is basically from inner ring and outer ring quantity, outer ring loose fit and integrated rib quantity. Also cage geometry and roller quantity can be different. 

FC, FCD and FCDP four rows CRB are used for kind of heavy machinery like cold rolling mill and hot rolling mill. Bearing ring and cage/roller assembly are separable which is convenient for leaning, check and installation/removal.

FC：

two outer ring have three integrated ribs and lubrication holes, one inner ring, both rollers guided two-claw brass cage.

FCD：

two outer ring have three integrated ribs and lubrication holes, two inner ring, both rollers guided two-claw brass cage.

FCDP：

two outer ring have one center rib, two loose fit retainer ring,  one spacer, lubrication holes; two inner ring, both rollers guided two-claw brass cage.