The 2032160 Strait-Line 5lb Black Chalk is what you need to help get things Strait. The Strait-Line black chalk is great for outdoor use, carpentry, bricklaying, masonary, roofing,carpet installation,floor and wall tiling, painting, decorating and many other uses. Black chalk is what you would need for a permanent line that will be able to endure the elements of the environment. Chalk containers are filled by weight not volume.