RARE ITEM ALERT!  MERCEDES ONLY INCLUDED THESE IN THE AMG ML55.  IT'S A PANEL THAT COVERS THE METAL LATCHES IN THE CARGO AREA THAT THE OPTIONAL THIRD ROW SEATS ATTACH TO.  SINCE THE ML55 HAD THE INTERIOR SPARE TIRE, THE THIRD ROW SEATS WERE NOT AN OPTION SO THEY DECIDED TO COVER THE HOLE UP.  THIS IS USEFUL AS IT MAKES THE ENTIRE CARGO AREA FLAT.  SNAPS RIGHT IN.