Set of (50) 11x14 Double Mat for 8x10 photo +Back+bag Set of (50) 11x14 Double Mat for 8x10 photo +Back+bag This item comes with 50 double mats, 50 bags, and 50 backing The opening size is 7.5"x9.5" for 8x10 print. The mats are beveled cut with white core and 4-ply thick (about 1.4 mm or 1/16 inch).