Depending on the shape of the space or {HEAD ~ the area} to be secured, the user can adjust {TAIL ~ the optical arrangement} 
Depending on the shape of the space or { HEAD ~ the area } to be secured , the user can adjust { TAIL ~ the optical arrangement }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL