the compressor end and towards the turbine end in this case the reverse imaged feature 109 is not fabricated into the bearing housing 3 in yet another variation of the second embodiment of the invention as depicted in fig6 b the male anti rotation feature 110 is fabricated to protrude the entire length of the reb cartridge and the reverse image feature is fabricated the entire length of the reb cartridge in the bearing housing to constrain the reb cartridge or outer bearing race from rotation about the turbocharger axis 100 relative to the bearing housing in this case the axial load towards the compressor end must be constrained by the bearing housing closure 6 or in some other manner fabricated the length of the bore in the bearing housing in the third embodiment of the invention as depicted in fig7 a and 7b a sleeve 79 of low thermal conductivity encapsulates the reb cartridge or outer race the function of this sleeve primarily is to restrict the flow of heat from the turbine housing through the bearing housing and into the outer race of the reb the sleeve per se can also be designed so as to provide an anti rotation function the reb cartridge or outer bearing race is encapsulated by a thermoplastic sleeve the end face of which has fabricated into it a male anti rotation feature 102 which slides into a female feature 103 in the turbine end face 87 of the bore 71 in the bearing housing 3 in the exemplary third embodiment of the invention this anti rotation feature is three asymmetrically spaced protrusions but it could be protrusions of any number or shape to adequately serve the function in a.