a plurality of gas outlet ports selectively in fluid communication with {HEAD ~ the plurality} of {TAIL ~ gas inlet ports} and first and second gas inlets of the processing chamber 
of
a plurality of gas outlet ports selectively in fluid communication with { HEAD ~ the plurality } of { TAIL ~ gas inlet ports } and first and second gas inlets of the processing chamber
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH