In the UPC symbology, {HEAD ~ a character} is defined as having two bars 16 and {TAIL ~ two spaces} 18 of varying widths 
is defined as having
In the UPC symbology , { HEAD ~ a character } is defined as having two bars 16 and { TAIL ~ two spaces } 18 of varying widths
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH