This is a whole or full plate 6.5x8.5" glass double sided plate holder. It looks to be in decent shape. There is black papers glued to the septum inside. Could be removed. Also two strips of wood added to the sides, could also be removed. With the strips, it measures about 8 1/8" wide; without strips, about 7 15/16". There is a slot, rather than rib.
$20 plus postage. Let me know if any questions.