IMC Marks heavy duty eco lumber crayons - wax-based crayon, comes in hardness level - 500. Lead-free, non-toxic. Bright and long-lasting marks. Weather and fade-resistant. Multi-surface marking, specially formulated for the lumber industry. Hex shape resists breakage and stops rolling. Marking temperature range from -10 to 200 degrees F (-23 to 93 degrees C). Applications: use on wet or dry lumber wood and timber. Marks on lumber, construction materials, utility poles, surveyor stakes, sewer and water pipe equipment, cardboard, concrete and paper. Orange color.