Weather and wear-resistant, the Keson Hard Lumber Crayon is designed to mark on wet and dry wood. Plus, it can also be used to write on concrete. Ideal for warmer climates, this lumber crayons is great for marking dry and wet wood, paper, cartons, stone, concrete, tiles, and plastic. It can last up to 10 times longer than ordinary molded wax crayons. On top of this, it is fade-proof, waterproof and smear proof.