Product Description This IRWIN STRAIT-LINE Standard Marking Chalk creates temporary marks that provide great visibility. The versatile formula is designed for both interior and exterior applications. Each bottle of IRWIN STRAIT-LINE marking chalk features a flip-top cap that is specially engineered for an airtight seal that keeps moisture out and minimizes clumping. From the Manufacturer Chalk Refill, 8 ounces of blue chalk refill for all reel type chalk line boxes, packaged in a plastic squeeze bottle with fast-fill spout, and snap cap to prevent spilling and moisture in chalk. Irwin tools are made of only the finest materials, manufactured to exacting tolerances.