Set of 50 pieces of 8x10 Picture Mattes for 5x7 Photos with 50 backing boards and 50 crystal clear sleeve folding flap bags. US Art Supply Brand Premium High Quality Mattes, Backers & Plastic Sleeve's that are all Made in the USA by Crescent. The opening size is 4.5"x6.5" for 5x7 photo prints. Color: Black. 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 sides.