{HEAD ~ A flexible diaphragm} situated in a rigid shell affixed over an opening in the element wall divides {TAIL ~ the shell interior} into first and second variable volume chambers 
divides
{ HEAD ~ A flexible diaphragm } situated in a rigid shell affixed over an opening in the element wall divides { TAIL ~ the shell interior } into first and second variable volume chambers
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH