Case top and bottom is Kappa binder's board (0.1), a bookmaking board with no glue between layers Lined with 10 point acid-and lignin-free card-stock PAT tested and passed Covered in book binding cloth with a moisture-resistant, 100% aqueous acrylic coating Adhesive is pH balanced and buffered, less than.0008% sulfur content Reinforced hinge, with dust flap Sides and spine are made of low-resin basswood Close-tolerance construction to keep out dust The tops of these boxes have a lip that helps keep out air-borne contaminates Thick walls of the case provide outstanding physical protection for the contents Sides and spine are made of low-resin basswood for superior stacking strength The top and bottom are thick (0.1) binder's board; Interior is lined with acid- and lignin-free card stock The spine of the case is hinged so that the top can fold open and lay flat for easy removal of contents When closed the box is sealed on all sides