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