Document 1, wherein {HEAD ~ said regions} made of {TAIL ~ magnetic material} are spaced by magnetically blank portions 
made of
Document 1 , wherein { HEAD ~ said regions } made of { TAIL ~ magnetic material } are spaced by magnetically blank portions
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH