The Boiler Makers Chalk (144pc Bulk) refers to a bulk pack of chalk sticks specifically designed for marking on metal surfaces, commonly used in metalworking, fabrication, and construction industries. The chalk is ideal for blueprints, cutting guides, and welding lines, as it leaves visible, clean marks on surfaces like steel, iron, or other metals. These chalk sticks are typically brightly colored (often white, red, or blue) for high visibility, and are easily erasable or wipeable. The 144-piece bulk pack is perfect for industrial use or large projects, providing ample chalk for multiple workers or extended use.