Uni Posca water-based pigment markers produce opaque, vibrant color and will on write on virtually any surface: paper, cardboard, tracing paper, rock, clay, cement, plastic, metal, wood, fabric, glass, canvas and more. The paint dries very quickly, especially on porous surfaces; Posca paint is permanent on porous surfaces, and removable on non-porous surfaces such as glass. This makes them perfect for temporary signage and window art.