This adapter sleeve provides a mounting interface for bearings with a tapered bore onto cylindrical shafting. The bore diameter is 125.0 mm, the design is standard, and the net mass is 4.46 kg. The sleeve is delivered as a complete mechanical unit, ready for fitting without additional machining. The tapered outer surface allows the bearing to be drawn up onto the sleeve, generating a controlled interference fit and setting the internal clearance during mounting. This construction simplifies mounting and dismounting on plain cylindrical shafts and allows axial positioning to be adjusted before the fit is locked in place with the lock nut and washer.