Amazon.com : Union Premium Foam Board 22 x 28 x 3/16" 10-Pack : Matte Finish High-Density Professional Use, Perfect for Presentations, Signboards, Arts and Crafts, Framing, Display (White, 22x28) : Office Products
BAZIC 22" X 28" Poster Board - White - Bazicstore
Pacon Poster Board Class Pack - Board and Banner - 22"Width x 28"Length - 50 / Carton - Assorted