This International Standard establishes a system for the designation of metric size tapered roller bearings produced in accordance with ISO 355. The system covers designations for single-row bearings, double-row bearings, and bearings with flanged outer rings. It also establishes designations for separate inner subunits (inner ring, tapered rollers and cage) and outer rings of such bearings. This International Standard does not apply to bearings or inner subunits or outer rings which in any respect deviate from ISO 355.