The 65101ZR Strait-Line 5lb Blue Chalk is what you need to help get things Strait. The Strait-Line 5 lb. blue chalk is great for indoor and outdoor use, carpentry, bricklaying, masonary, roofing,carpet installation,floor and wall tiling, painting, decorating and many other uses. Blue chalk is great for temporary lines that will disapear after a while. For more than 30 years, Strait-Line products have represented the standard for excellence and performance in marking tools.