Strong 3 1/4" x 3 1/2" card pockets made from tough acid-neutral stock with reinforced edges for added strength. For 3" x 5" cards. Ready for pasting in books. 500 per box. Self Adhesive Library Card Pockets - Size: 3 1/4"H x 3 1/2"W with 2 1/2"H pocket. 500 per box. Self Adhesive High Back Date Due Library Card Pockets - Size: 6 1/4"H x 3 1/2"W with 2 1/2"H pocket. Date due grin printed on top of card above pocket. 500 per box.