Solid Marker writes on smooth; rough; oily and wet surfaces. Ideal for asphalt; concrete; masonry; windshields; glass and plexiglas; lumber; cardboard; PVC pipe; plastic tubing; steel plates; beams; sheet metal; shrinkwrap and plastic sheeting. Permanent; nontoxic ink is fade-resistant and waterproof. Marks on almost any surface in any weather condition. Performs in a broad range of temperatures whether hot or cold. Marker even marks under water and through running water like rain running down the side of a building. Marker is a solidified stick of paint in a plastic barrel with easy-to-use twist-up mechanism to advance the paint material.