11x17 Mat Board Uncut Variety Pack 10 Assorted Colors This item comes with 10 matboards The mats are Cream core and 4-ply thick (about 1.4 mm or 1/16 inch). 11x17 UNCUT mat matboard Assorted Color This is acid Free, Neutral Ph great for Matting. White Core, Great Looking color 10 Best Selling Colors, Vibrant Colored Surface Papers