Golden State Art Pack of 5, 16x20 Black Picture Mats Mattes with White Core Bevel Cut for 11x14 Photo + Backing + Bags Pack of 5 16x20 Black Picture Mats Mattes with White Core Bevel Cut for 11x14 Photo + Backing + Bags This item comes with 5 single mats, 5 backing, and 5 bags. The 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.