{HEAD ~ A single vent} is located between the cells and {TAIL ~ drains} fluid or gas, as the case may be, from the cells 
is located between
{ HEAD ~ A single vent } is located between the cells and { TAIL ~ drains } fluid or gas , as the case may be , from the cells
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH