Polystyrene extruded foam laminated between two sheets of paper to form a lightweight but strong and rigid surface. Ideal for crafts, school projects, framing, mounting, displays and exhibits. It has a smooth surface that can accept a wide range of media, including paints. Sheets are 3/dev46" thick and are easy to cut. Measures 20" x 30". Includes 10 sheets, 5 sheets of White, and one sheet each of Black, Blue, Green, Red and Yellow.