Extruded lumber crayons last up to 10X longer than ordinary molded wax crayons. Fade proof, waterproof, smear proof. Won't melt in direct sunlight. Will work on wet (green) lumber or dry wood, metal, concrete and most other surfaces. Each crayon is individually UPC coded. Hex shaped 4-1/2 x 1/2 in to fit lumber crayon holders. Eleven colors to choose from. One dozen per box.