To prevent leakage of gas from within the cell the substrates have sealing areas 24 at {HEAD ~ opposite edges} to cooperate with {TAIL ~ the sealing surfaces} on the plates 
to cooperate with
To prevent leakage of gas from within the cell the substrates have sealing areas 24 at { HEAD ~ opposite edges } to cooperate with { TAIL ~ the sealing surfaces } on the plates
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH