Filter panels are removably attached to the outer surfaces of the edges and {HEAD ~ filter material} is mounted in {TAIL ~ the panels} to cover the empty spaces 
Filter panels are removably attached to the outer surfaces of the edges and { HEAD ~ filter material } is mounted in { TAIL ~ the panels } to cover the empty spaces
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH