a surrounding ferrous cylindrical case having an enclosing configuration and a hollow interior, said {HEAD ~ case} having an outside surface, {TAIL ~ an inside surface}, and a central axis, 
having
a surrounding ferrous cylindrical case having an enclosing configuration and a hollow interior , said { HEAD ~ case } having an outside surface , { TAIL ~ an inside surface } , and a central axis ,
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH