{TAIL ~ The flow field plates} are an assembly of {HEAD ~ a cathode side unipolar plate} and an anode side unipolar plate 
{ TAIL ~ The flow field plates } are an assembly of { HEAD ~ a cathode side unipolar plate } and an anode side unipolar plate
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH