Special rear hub bearing for use with Casa Performance Octopus multi-spline hear hub X74. The reason we supply a special rear hub bearing for use with the Octopus rear hub is that splined hubs such as these, require a larger centre 'ring' of the wheel bearing to sit up against and therefore a smaller than standard oilseal is needed - and that too is supplied with the bearing. This bearing can also be used in ANY Lambretta S1 + S2 + S3 + DL GP + Serveta engine.