The Masterson Sta-Wet Painter's Pal Palette Sponge Refill is compatible with the Masterson Sta-Wet Painter's Pal Palette. The sponge is designed to be used in combination with the Masterson Sta-Wet Acrylic Palette Paper (not included) to provide moisture for the Sta-Wet system. The sponge is reusable. When moistened and used in the Sta-Wet system, the sponge keeps acrylics and other water-soluble paints workable for days and even weeks. The Sta-Wet Painter's Pal Sponge Refill includes 1 sponge. Please be sure to follow all sponge preparation instructions provided. Made in the USA.