Professional-grade semi-permanent red marking chalk designed for use in chalk line reels for long-lasting layout, marking, and reference lines on construction, concrete, and outdoor projects. Manufactured by KESON with ProChalk semi-permanent formula in convenient 5-pound container for high-volume commercial and residential applications. This specialized red chalk resists rain, moisture, and weathering to maintain visible lines over extended periods, making it ideal for outdoor concrete projects, foundation work, and applications requiring marks that won't wash away easily.