"Set of 100 pieces of 5x7 Picture Mats for 4x6 Photo with backing boards and bags This item comes with the 100 pre cut mats, 100 backing boards and 100 clear bags. The opening size is 3.5""x5.5"" for 4x6 print. Color: WHITE 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. The re sealable adhesive strip of the clear bag is below the opening of the bag instead of on the flap."