Keson ProChalk & Glo Marking Chalks -Strike once, strike bold! ProChalk is formulated to achieve a prefect line every time. Brilliant color tones provide strong, sharp lines. From the brightest pigments in the industry, we produce standard colors plus our unique, fluorescent & Glo-Orange & Glo-Lime for improved visibility. There's no way to miss a line like this. Standard grade marking chalk. Up to 8 lines possible with proper techniques. 4-5 strikes usual line yield. Brilliant color. Great flow for easy box fill