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