An edge coating of polymer or other material is disposed on and seals the interior edge of the base sheet and may project beyond the facial planes of {HEAD ~ the base sheet} to define {TAIL ~ protruding rims} extending around the aperture 
to define
An edge coating of polymer or other material is disposed on and seals the interior edge of the base sheet and may project beyond the facial planes of { HEAD ~ the base sheet } to define { TAIL ~ protruding rims } extending around the aperture
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH