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