Golden State Art, Pack of 20 11x14 BLACK Picture Mats with White Core Bevel Cut for 8x10 Pictures Pack of 20 11x14 BLACK Picture Mats with White Core Bevel Cut for 8x10 Pictures. This item comes with 20 11x14 single mats. Inside (opening) Size: 7.5x9.5 (bevel cut), Color is Black. White core and 4-ply thick (about 1.4 mm or 1/16 inch). THIS ITEM DOESN'T INCLUDE BACKING BOARD.