Owens Corning FOAMULAR 250 2 in. x 48 in. x 8 ft. R-10 Scored Squared Edge Foam Board Insulation Sheathing 52DD - The Home Depot
High-Quality Extruded Polystyrene XPS - The Foam Company
POLYSTYRENE FOAM SHEETS - Foam Mart
Amazon.com: AMZQNART Craft Foam Blocks, 1 in Thick 17x11" EPS Polystyrene Rectangle Foam Blocks Packs of 7 Pcs for Art Sculpting, Sculpture, Modeling, School and Home DIY. : Arts, Crafts & Sewing