In {HEAD ~ other embodiments}, the joiner may be provided with {TAIL ~ an air outlet portion} such as a diffuser outlet 
In { HEAD ~ other embodiments } , the joiner may be provided with { TAIL ~ an air outlet portion } such as a diffuser outlet
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH