Image Item No. Description By  87580  Plate, Modified 2 x 2 with Groove and 1 Stud in Center (Jumper) Catalog: Parts: Plate, Modified 18  92099  Plate, Modified 4 x 6 with Trap Door Hinge (Long Pins) Catalog: Parts: Plate, Modified 1  92107  Plate, Modified 6 x 8 Trap Door Frame Horizontal (Long Pin Holders) Catalog: Parts: Plate, Modified 1