These have outward-facing types (for double-row outer ring use) and inward-facing types (for double-row inner ring use). As the inner clearance is adjusted to a set value, the bearings must be used in combination with components of the same product number, as marked.
In addition to duplex bearings that combine a pair of single row tapered roller bearings, there are also four-row tapered roller bearings composed of two double-row inner rings, one double-row outer ring, and two single-row outer rings. Four-row tapered outer bearings are used in high-load applications such as rolling mill roll necks.