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