Dixon Industrial Lumber Crayons - Hexagon - 4-1/2 x 1/2 in - Black - 12 PackDixon Lumber Crayons last up to 10 times longer than ordinary molded wax crayons. Fade proof, water proof, smear proof, these crayons won't melt in direct sunlight. They will work on wet (green) lumber or dry wood, metal, concrete and most other surfaces. Each crayon is hex shaped (4 1 2 x 1 2 inches) to fit lumber crayon holders. One dozen per box.