Golden State Art, Pack of 25, 16x20 Black Picture Mats Mattes with White Core Bevel Cut for 11x14 Photo + Backing + Bags Pack of 25 16x20 Black Picture Mats Mattes with White Core Bevel Cut for 11x14 Photo + Backing + Bags This item comes with 25 single mats, 25 backing, and 25 bags. The mat opening size is 10.5"x13.5" for 11x14 print. The mats are beveled cut with white core and 4-ply thick (about 1.4 mm or 1/16 inch). The re-sealable adhesive strip of the clear bag is below the opening of the bag instead of on the flap.