Amazon.com : Excelsis Design 15 Pack Foam Board 20x30 Inches | White Foam Board 1/8 Inch Thick White Core Mat | Backing Board for Presentations, Signboards, Arts, Display and Crafts with Double-Sided
Jerry's Pro Foam Board Box of 15 32x40 (3/8 Thick) White | Jerry's Artarama
BAZIC 20" X 30" Fluorescent Green Foam Board - Bazicstore
Mat Board Center, Pack of 10 1/8" White Foam Core Backing Boards (5x7, White) - Walmart.com