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