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.