{TAIL ~ an electrically conductive metallic casing} having {HEAD ~ a passageway therethrough} and an interior wall, 
{ TAIL ~ an electrically conductive metallic casing } having { HEAD ~ a passageway therethrough } and an interior wall ,
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH