This adapter sleeve provides the mounting interface between a bearing with a tapered bore and a straight shaft, allowing the bearing to be fitted on standard cylindrical shaft sections. The bore diameter is 85.0 mm, the net mass is 2.042 kg, and the design is standard. It is a complete mechanical accessory component, designated H2319, intended for use with rolling bearings requiring this adapter mounting method. Fitting the bearing on the shaft via this sleeve allows precise control of the internal clearance during mounting, as the sleeve is driven up the taper to achieve the correct fit. This mounting method simplifies installation and removal compared to a directly tapered shaft, and is suited to applications where the bearing needs to be positioned on a plain cylindrical shaft while retaining the mounting characteristics of a tapered-bore bearing.