Post bound Top Loading Page Protectors-Black-5PK/8 1/2 Inch x11 Inch Heavy paper black inserts with top loading sheet protectors (5) Postbound and polypropylene; acid free, lignin free and PVC emission free Fits all 8-1/2 Inch x11 Inch Pioneer albums plus most other postbound & strap hinge albums Archival, Photo Safe: Acid, Lignin and PVC Free