Amazon.com: Sibe-R-Plastics Supply - Coroplast Sign Boards, 24" x 36", Corrugated Plastic Poster, Set of 2 : Industrial & Scientific
Corrugated Board, E-Flute Archival Grade – MuseuM Services Corporation
Coroplast/Corrugated Plastic (Fluted Polypropylene) – Atlantic Graphic Systems, Inc.
Amazon.com: 24x48 4mm Corrugated Plastic Sheets 5 Pack Blue Waterproof Lightweight, Blank Boards Double Sided for Lawn Signs, Garage Sales and Real Estate. Various Sizes, Colors by WholesaleArtsFrames-com : Industrial & Scientific
Amazon.com : Corrugated Plastic Sheet for Indoor and Outdoor Use - 3/16 Inch Thick Poster Board, 24x36 Inches - Pack of 5 White Plastic Board Sheets - Waterproof Coroplast Sheets and Lightweight