{HEAD ~ The anchor} is {TAIL ~ an elongate cylindrical shell} with a central passage to receive the bolt, thereby forming an anchor bolt unit 
is
{ HEAD ~ The anchor } is { TAIL ~ an elongate cylindrical shell } with a central passage to receive the bolt , thereby forming an anchor bolt unit
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH