These parts are identified with {HEAD ~ reference} to {TAIL ~ the position} of the tool shown in FIGS 1 and 3 
to
These parts are identified with { HEAD ~ reference } to { TAIL ~ the position } of the tool shown in FIGS 1 and 3
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH