This item comes with 50 pre-cut mats, 50 backing boards and 50 clear bags. The opening size is 11cm x 17cm for 5x 7 print. The mats are bevelled 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 cream core matboards are a 4-ply paper mat that provide the aesthetic and design benefits of a bright cream bevel. It can be used for matting photos, art, and needlepoint. Also great for crafts, backboards, signs, children's projects, and school projects.