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