the dirty air conduit 110 and the collar 118 is configured to receive the ring 120 therein the collar 118 threadedly engages the upper end of the exhaust conduit 106 and screws down onto it the elastomeric ring 120 is thereby compressed between a shoulder internal to the collar 118 and the upper end of the exhaust conduit 106 the compression of the ring forces the ring 120 to expand into tight engagement with the adjacent surface of the dirty air conduit 110 which retains the dirty air conduit 110 against axial movement out of engagement with the exhaust conduit 106 in normal use the lower end 122 of the exhaust duct 112 includes a threaded region 124 and can be mounted to the dirty air conduit 110 in like manner to the mounting of the dirty air conduit 110 to the exhaust conduit 106 a tab not shown on the interior of the exhaust duct 112 is received in a slot 126 in the upper end of the dirty air conduit 110 substantially filling the slot 126 a collar 128 and elastomeric ring 130 are slid over the upper end 132 of the dirty air conduit 110 and the collar is screwed onto the lower end 122 of the exhaust duct 112 compressing the ring 130 and causing it to frictionally engage the adjacent wall of the dirty air conduit 110 the vacuum cleaner 100 is.