Rubbermaid Lid for Bento Storage Boxes, Medium, Chadwick (1789304) Bento Toppers can act as trays, covers or lids, providing an extra layer of organization or hide whats inside. The heavy-duty decorative polyester fabric coating enables it to fit into social spaces and complement your homes dcor. Made from sturdy CARB-certified MDF. Bento boxes have internal flex dividers that let you create custom, unique sections as you need them. Boxes can stack vertically, or fit inside each other.