components thereby to form a fluid tight seal between them the second component may be at least partially enclosed between the first and a third component and the second component may provide an aperture at a location opposite a portion of the third component whereby expansion of a seal means around the aperture causes the aperture to be sealed by the seal means and said portion of the third component application_number US 201214117076 A description fig1 is a perspective view of a sub woofer baffle tray 110 according to an embodiment of the present invention the tray 110 is arranged to be coupled to an underside 150 u of a floor panel 150 of a motor vehicle floorpan assembly 155 fig2 thereby to define a box portion of a sub woofer system the tray 110 is of substantially u shaped square cross section defined by two elongate parallel side walls 110 a 110 c and a basal wall 110 e a pair of end walls 110 b 110 d are provided at opposed ends of the side walls 110 a 110 c and basal wall 110 e lateral web members 110 w are provided within the tray 110 oriented transverse to a longitudinal axis thereof in order to increase a stiffness of the tray 110 this allows a reduction in thickness of walls 110 a 110 c 110 b 110 d of.