Foam Board, Cfc-free Polystyrene, 20 X 30, Black Surface And Core, 10/cartonAdd dimension to your creativitythese boards are ideal for creating artwork or completing school projects. Designed for durability, lightweight foam display boards feature a polystyrene memory core that expands back into shape after cutting for a consistent thickness from edge to edge. Each foam board features smooth surfaces that are perfect for pencils, markers, paints, adhesives and fabrics. Strong enough to resist crushing and denting.