This Montana Cans Chalk Spray has the look and feel of a rough chalk effect, ideal for temporary outdoor markings on non-porous surfaces as well as for indoor studio artwork. This is a great medium for signage for events, advertisements, marketing campaigns and outdoor activities. Apply this spray on various surfaces such as sidewalks, walls, cardboard and canvas. The chalk markings will last from several weeks to several months, depending on climate and weather conditions. The chalk color pigments will wash away faster on non-porous surfaces like glass or metal, but some pigments may remain on porous surfaces.Details:Available in assorted colors400 mLTemporary markings on non-porous surfacesNon-hazardous to plantsFinish artwork with spray varnish to create long lasting permanent effectsConforms to ASTM D-4236