These archival sheet protectors are refill pages designed to expand multiring portfolio books, presentation cases, and display easel binders beyond their included page count. Made from archival-grade polypropylene, sealed on three sides, and loaded from the top, each protector includes an acid-free black paper liner and meets ANSI requirements for archival storage. Compatible with Florence, Alvin, Prat, and all standard-pitch multiring portfolios.