Lineco Cotton Rag Museum Mounting Boards are 4-ply matboards made from 100% cotton fibers, with solid color throughout. Every board is acid-free, lignin-free, and buffered with 3% calcium carbonate. These affordable, high-quality boards don't compromise on quality. - Lineco Cotton Rag Museum Mounting Boards - Pkg of 25, White, 11" x 14"Museum Mounting Boards, WHT 25PK 11X14IN -