20 16x20 White w/ Blackcore for 11x14 + backing + bags 20 16x20 White w/ Blackcore for 11x14 + backing + bags This item comes with 20 11x14 single mats, 20 backing, and 20 bags The opening size is 10.5"x13.5" for 11x14 print. The mats are beveled cut with black core and 4-ply thick (about 1.4 mm or 1/16 inch).