Abstract: This invention relates to a housing, preferably but not exclusively for use with a motor vehicle heater of the type employed to heat the passenger compartment of the motor vehicle. The housing has a unitary housing body formed by blow moulding and a structural frame is formed by injection moulding. The structural frame bears the load of internal components within the housing body, enabling the housing body to be made with very thin walls in order to reduce its weight. The housing body has integrally formed internal walls to guide the flow of air.

Abstract: An apparatus for expanding a tube 1 from a first diameter d.sub.1 to a second diameter d.sub.2 by passing a mandrel through a tube 1 includes a bullet assembly 3 comprising at least two co-operating bullet segments 5, 7, 9, Each of the bullet segments 5, 7, 9 has an outer surface 11 for contacting the inner surface of the tube and an inner surface 13 for contacting the inner surface of an adjacent bullet segment. The outer surface 11 of each segment is generally arcuate in radial cross-section and each segment has a body region 15 between a head 17 and tail region 19. The inner surfaces 13 of adjacent bullet segments 5, 7, 9 have co-operating tapered surfaces 21 shaped such that the bullet segments are movable axially with respect to one another such that the bullet assembly 3 may be in an expanded state or a collapsed state.