Pinit Archival-Grade 18 x 24" Matboard with Window. 100% pure Alpha-Cellulose. White core and back. 4-Ply. Available in 18 face paper colors. Click on window size 11 x 17, 12 x 18 or 13 x 19" Click on color swatch to choose desired color. SKU: KMB1824w (0)No Reviews yet Add to Shopping Cart Details 'Select' Archival-Grade Matboard18 x 24" with Window 100% Pure Alpha Cellulose White Core & Back.4-Ply .060" thick. Buffered, Acid-free, lignin-free.C... Details Back Details'Select' Archival-Grade Matboard18 x 24" with Window 100% Pure Alpha Cellulose White Core & Back.4-Ply .060" thick. Buffered, Acid-free, lignin-free.Choose window size - 11 x 17", 12 x 18" or 13 x 19" Choose matboard color -18 choices Reviews 0 Back Ratings & ReviewsNo reviews availableBe the first to Write a Review