said {TAIL ~ mounting fixtures} being capable of inverting {HEAD ~ a mounting direction} of said device relative to a second user; and 
said { TAIL ~ mounting fixtures } being capable of inverting { HEAD ~ a mounting direction } of said device relative to a second user ; and
OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH