Acid-Free Foam Core Boards - Artist & Craftsman Supply
20" x 30" Acid Free Foam Boards, 2ct. | Michaels
5 x 7 Acid Free White Foamcore 3/16 (Pak of 50) - MatShop Art Supplies
Amazon.com: Jerry's Artarama Acid-Free Foam Board Sheets for Artists and Framers 8"×10" (3/16" Thick), Box of 25 - Ideal for Mounting and Cutting, White Foam Poster Board, Foam Core Board - White :
Elmer's Foamcore Acid Free 20"x30" 3/16" 2-Pack - RISD Store
Elmer's Acid-Free Foamboard, 3/16" x 32" x 40", Cream - Sam Flax Atlanta