Made from acid-free weather-resistant thick polypropylene it is both light-weight and durable. Built-in magnetic closure makes it quick and easy to open and close. Safely and securely protects your art or pages up to 1/4" thick. Archival quality. Hard black polypropylene cover Strong magnetic snap closure protects contents Max capacity 1/4" thick material Opens up to lie completely flat Inside dimensions 9" x 12" x 1/4" Outside dimensions 9-1/4" x 12-3/8" x 1/2"