{HEAD ~ an end cap} coupled to the stack for defining {TAIL ~ an anode air stream plenum} in fluid communication with the anodes 
{ HEAD ~ an end cap } coupled to the stack for defining { TAIL ~ an anode air stream plenum } in fluid communication with the anodes
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH