A tray may also be removably secured in the channels of {HEAD ~ the display board extrusions} in {TAIL ~ selected removably secured positions} 
in
A tray may also be removably secured in the channels of { HEAD ~ the display board extrusions } in { TAIL ~ selected removably secured positions }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL