Elmer's Acid-Free Foam Boards, 20 x 30 Inches, 3/16-Inch Thick, Bright White, 2-Count (902015) Protection from deterioration - Resists humidity and atmospheric pollutants Bright white finish dramatically enhances colors of any artwork Perfect for mounting posters and photographs Smooth surface for a wide range of mediums 20 x 30 inch size - Pack of 2 bright white foam boards