This adapter sleeve provides a mechanical mounting interface between a shaft and a bearing with a tapered bore, allowing the bearing to be fitted at the correct position along the shaft length. It has a bore diameter of 25.0 mm and a net mass of 0.101 kg, corresponding to the standard design H206. The tapered outer surface of the sleeve creates the required interference fit when driven onto the shaft, which sets the internal radial clearance of the bearing during installation. Using this sleeve allows the bearing to be mounted on plain cylindrical shaft sections without a stepped or shouldered seat, and the fit achieved determines the correct running clearance for the assembled bearing.