Clear 'n' Easy Book Covers come in individual sheetsoron rolls. Made from 1.5 mil archival polyester. Polyester material will not yellow or become brittle over time, even in direct sunlight.Both the individual sheetsand the rolls have a pre-folded 1-1/2" flap on one long edge. Simply insert book jacket under the pre-folded edge and fold other long edge over book jacket cover. Covers come with an optionaluse adhesive tab to keep the cover in place.