Designation via standards:
LM300849/LM300811 ANSI/ABMA 19.2;
LM300849 inner ring and cage with taper roller;
LM300811 outer ring
The bearing consists of two rings (inner and outer) and rolling elements (tapered rollers) which are connected by a cage. The inner ring with a cage and rolling elements is a CONE. The outer ring is a CUP.
The design of tapered roller bearings suites for the perception of combined (radial and axial) loads. Tapered roller bearings have a split construction: the inner ring with the rollers and separator create the unit, that can be mounted separately from the outer ring.