Our Sponges for Watercolor Paint are a great help for people who like to paint with watercolors on wet paper. The paper is put in water for a minute. Then when it is taken out, you gently wipe the wet paper with the firm edge of this little sponge. The paper will be ready for watercolor painting, just like in the Waldorf preschools and kindergartens. These 3" x 4" x 3/4" sponges are made from pressed wood and cotton fibers. Sold in sets of three, they come flat, put in water and watch them expand! Made in the USA.