{HEAD ~ Each} of {TAIL ~ the casings} includes a coverable opening through which the electrolyte solution within the cell is replaceable 
of
{ HEAD ~ Each } of { TAIL ~ the casings } includes a coverable opening through which the electrolyte solution within the cell is replaceable
HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH