Mat Board Center, Crescent Pack of 50 sets 5x7 MIXED COLORS White Core Picture Mats Mattes Matting for 4x6 Photo + Backing + Bags Crescent High Quality Set of 50 pieces of 5x7 White Core Picture Mats for 4x6 Photo with backing boards and bags The opening size is 3.5"x5.5" for 4x6 print. Color: Mixed color The re-sealable adhesive strip of the clear bag is below the opening of the bag instead of on the flap. This item comes with the 50 pre-cut mats, 50 backing boards and 50 clear bags. 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 side.