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