Durable, top-loading document sleeve protects important letter-size papers with ultimate protection. Clear design allows you to easily view documents inside. Nonstick coating prevents ink from smudging or rubbing off papers onto the sheet protector. 5 mil thick sheet protector is made from super-heavyweight polypropylene that is acid-free and archival-safe. Sheet protectors are 11-hole punched along the reinforced binding edge to fit virtually any binder.