To mark easily on tough surfaces, use C.H. Hanson's El Marko® Red Traditional Lumber Crayon. This crayon creates distinct and readable marks, and works perfectly with wood or concrete. Extend the life of your crayon by investing in Crayon Armor, the best casing to protect your lumber crayons.
Marks on wood, metal, and concrete
Waterproof
Measurements: 1/2" wide x 4 1/2" working life with Crayon Armor®