Golden State Art, Pack of 5 Black Pre-Cut 16x20 Picture Mat for 11x14 Photo with White Core Bevel Cut Mattes Sets. Includes 5 High Premier Acid Free Mats & 5 Backing Board & 5 Clear Bag Set includes: 5 16x20 Black Mats, 5 Backing boards, & 5 Clear Bags The mat opening size is 10.5"x13.5" for 11x14 print. The mat is 4-ply thick (about 1.4 mm or 1/16 inch). Backing Board Color is White on both sides. The clear bag has re-sealable adhesive strip below the opening of the bag instead of on the flap.