Mat Board Center Premier Crescent Acid-Free Pre-Cut 8x10 White Picture Mat Sets. Includes a Pack of 25 White Core Bevel Cut Mattes for 5x7 Photos, Pack of 25 Backers & 25 Clear Bags Set of 25 pieces of 8x10 Picture Mattes for 5x7 Photos with 25 backing boards and 25 crystal clear sleeve folding flap bags. Premium High Quality Mattes, Backers & Clear Plastic Sleeve Bags The Mat opening size is 4.5"x6.5" for 5x7 photo prints. Color: White. The mats are beveled cut with white core and 4-ply thick (about 1.4 mm or 1/16 inch), The backing is white on both sides. The re-sealable adhesive strip of the clear bag is below the opening of the bag instead of on the flap.