{HEAD ~ Other installations} may require {TAIL ~ the substitution} of a screw eye near the rear end of the mailbox 
require
{ HEAD ~ Other installations } may require { TAIL ~ the substitution } of a screw eye near the rear end of the mailbox
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH