Such a mounting surface 101 is usually vertically positioned in {HEAD ~ the vicinity} of a window or {TAIL ~ other architectural opening} 
Such a mounting surface 101 is usually vertically positioned in { HEAD ~ the vicinity } of a window or { TAIL ~ other architectural opening }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL