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