Brodart 15 Yard Combo -- Just-a-Fold III Archival Book Jacket Covers (9", 10", 12") PLUS 8" Genuine Bone Folder One 5 (five) yard roll each of 9", 10" and 12" Genuine Brodart Just-A-Fold III dust jacket covers PLUS one Genuine 8" Bone Folder! pH neutral PVA Adhesive and Chemically stable 1.5 mil thickness polyester. Super Clear polyester mylar allows DJ Brilliance to show through and prevents books from sticking together on the shelves. Bottom Loading - Allows flexibility with different size book jackets. Can be folded several inches smaller than stated size. Non-printed, acid-free paper backing with perforated folding lines for ease in fitting and added protection