said mounting fixtures are capable of inverting {HEAD ~ a mounting direction} of {TAIL ~ said device} relative to said first user, 
of
said mounting fixtures are capable of inverting { HEAD ~ a mounting direction } of { TAIL ~ said device } relative to said first user ,
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH