This is the first distance of travel the temple may flex beyond {HEAD ~ its fully open, unbiased position} on {TAIL ~ the eyewear} 
on
This is the first distance of travel the temple may flex beyond { HEAD ~ its fully open , unbiased position } on { TAIL ~ the eyewear }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL