These polypropylene sheets feature superior scratch resistance to make your work look better longer, a non-stick finish to prevent adhesion to your artwork and a non-reflective finish to minimize glare. All formats are top-loading. Made of inert, unplasticized, heat resistant and chemically stable archival quality, heavy-duty .0045 polypropylene.These sheets have passed the Photographic Activity Test (PAT) and meets all ANSI requirements for archival storage. Packed in tens in a protective metallic, resealable bag.