Black lumber crayon #500 wax-based marker. Marking range from -20 degree F to 150 degree F (-28 degree C to 66 degree C). All-purpose marker for all surfaces. More economical, longer lasting than ordinary wax crayons. 1/2" hex shape resists breakage and stays put without rolling onto the floor. The new fluorescent colors work well with the new computerized, scanner-equipped, cut-off saws. #500 - harder crayon marks easily in hot climates.. Weather-resistant, fade-resistant colors. Lead-free, non-toxic. Ideal for lumber, concrete, metal, plastic, rubber, ceramics, cardboard, smooth or rough surfaces, construction materials, utility poles, surveyor stakes, sewer and water pipe equipment, paper marking.