said {HEAD ~ core} having {TAIL ~ a central axis} which coincides with said axis of said surrounding ferrous cylindrical case, 
having
said { HEAD ~ core } having { TAIL ~ a central axis } which coincides with said axis of said surrounding ferrous cylindrical case ,
OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH