Brodart Fold-On Archival covers protect your dust jacket which ultimately protects your book. These high quality book jacket covers are Center-Loading for Dust Jackets. The polyester mylar covers are 1.5 mil in thickness. Fold-On Archival covers are crystal clear and have a glossy finish to show off new book graphics. The polyester is acid-free, chemically inert and will not yellow or crack with age. They come with permanently adhered, non-printed, acid-free paper backing. A pH neutral PVA adhesive is used to bond the paper back to the polyester. This product is NOT FOR CHILDREN. Brodart's Fold-On Archival book jacket covers are acid-free, chemically inert and will not yellow of crack with age. They are made with super-clear polyester mylar with acid-free, non-printed paper backing. The PVA adhesive is pH neutral. These are center loading covers which fold down to a custom fit. These sheets will fit any dust jacket up to 9 inches tall, and the length can be cut to fit any width. This product is NOT FOR CHILDREN.