YUPO Medium Bulk includes 50 74lb sheets that measure 9 by 12 inches. Featured in a durable box to store within your studio or classroom, YUPO is ideal for watercolor, alcohol ink classes as well as large volume personal use. YUPO is synthetic made from 100 percent Polypropylene and is waterproof. The surface is unlike any other paper in that with watercolors it can be wiped completely clean! Discover the forgiving and endless possibilities of YUPO paper with watercolor, alcohol inks, pencil and markers. Great for aspiring artists! Acid free and archival.