Lumber crayons color=blue Extruded lumber crayons last up to 10 times longer than ordinary molded wax crayons. Fade proof, water proof, smear proof; won't melt in direct sunlight. Will work on wet (green) lumber or dry wood, metal, concrete and most other surfaces. Hex shaped 4-1/ 2 inches x 1/2 inches to fit lumber crayon holders. One dozen per box.