Strathmore Cards clear plastic sleeves are archival grade, acid free and lignin free to provide the ultimate protection for your stationary, photographs or printed matter. made of the higest grade of virgin 1.6 mil polypropylene. These sleeves have an adhesive strip on the outside body of the holder to allow for easy removal and reinsertion of the contents. Sleeves measure 5.4375 x 7.25 inches, pack of 25.