This item comes with 25 pre-cut mats, 25 backing boards and 25 clear bags. The opening size is 7.5 x 9.5 for 8 x 10 print. The mats are beveled cut. The backing is also 4-ply. The re-sealable adhesive strip of the clear bag is below the opening of the bag instead of on the flap. Our acid-free whitecore matboards are a 4-ply papermat that provide the aesthetic and design benefits of a bright white bevel. It can be used for matting photos, art, and needlepoint. Also great for crafts, backboards, signs, children's projects, and school projects.