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