BPack of 50 White 16x20 Mats for 12x18 Photo + Backing + Bags ReviewbP PP Pack of 50 White 16x20 Mats for 12x18 Photo + Backing + Bags PPack of 50 White 16x20 Mats for 12x18 Photo + Backing + BagsPThis item comes with 50 mats, 50 backing, and 50 bagsPThe opening size is 11.5"x17.5" for 12x16 print.PThe mats are beveled cut with white core and 4-ply thick (about 1.4 mm or 116 inch).