US Art Supply Art Mats Acid-Free Pre-Cut 16x20 Black Picture Mat Matte Sets. Includes a Pack of 10 White Core Bevel Cut Mattes for 11x14 Photos, Pack of 10 Backers & 10 Clear Sleeve Bags Set of 10 pieces of 16x20 Picture Mattes for 11X14 Photos with 10 backing boards and 10 crystal clear sleeve folding flap bags. Art Mats&trade; Brand Premium High Quality Acid-Free Mattes, Backers & Plastic Sleeve's The opening size is 10.5 x 13.5" for 11x14 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. The set is professionally Packed and Boxed to Assure that All Precautions have been made for a Save Arrival of your purchase. The opening size is 10.5&#034;x13.5&#034; for 11x14 photo prints The mats are beveled cut with white core and 4-ply thick (about 1.4 mm or 1/16 inch), The backing is black on both sides Mat board is suitable for general purpose framing and is acid-free 10<span class="a-text-bold"> - 16x20</span> Picture Matte Frames for 11x14 Photos 10 - Backing boards 10 - Crystal clear sleeve folding flap bags