Irwin Strait-Line Blue Lumber Crayon is a durable and reliable marking tool designed to meet the needs of professionals and DIY enthusiasts alike. Measuring 4-1/2 inches, this crayon features a tough compound that ensures waterproof marking and long-lasting performance. It is versatile enough to be used on a variety of surfaces including oily, slick, wet, cold, or dry conditions. Whether you need to mark wood, concrete, metal, rubber, plastic, cardboard, or ceramic, this wax-based and nontoxic crayon delivers clear and precise lines every time. Its vibrant blue color stands out for easy visibility on different materials, making it an essential tool for construction, carpentry, and other projects requiring accurate markings. Model Number: 66402