PSS 20® is a breathable, completely reversible, and indiscernible system for protection against many outdoor uses: graffiti, tape and adhesive, gum, heel marks, and airborne soiling. This product can be used on many different surfaces: masonry, concrete, stone, and mineral-painted surfaces. It can also be used on interior or exterior facades, walls, planters, etc. PSS 20 is a high-viscosity vegetable polysaccharide solution made of water. It is completely biodegradable and safe to use. PSS 20 is a natural, sustainable product that is harmless to humans, animals, and the environment. Only professionals and skilled tradesmen should apply it.