Irwin Strait-Line Black Lumber Crayon is a durable marking tool designed to deliver waterproof and long-lasting marks. Measuring 4-1/2 inches, this crayon features a tough compound that performs well on a variety of surfaces including oily, slick, wet, cold, or dry conditions. It is i for use on wood, concrete, metal, rubber, plastic, cardboard, and ceramic materials. The wax-based formula is nontoxic, making it safe for everyday use while providing reliable visibility in different environments. Model Number: 66404