This variation in size will usually produce {TAIL ~ the necessary density} and {HEAD ~ incompressibility} when in use as to minimize the leakage from the cell 
This variation in size will usually produce { TAIL ~ the necessary density } and { HEAD ~ incompressibility } when in use as to minimize the leakage from the cell
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH