This is a professional-grade 1-gallon jug of CLR PRO Calcium, Lime, and Rust Remover, specifically formulated for facilities maintenance and heavy-duty industrial use. The original formula is designed to quickly dissolve tough mineral deposits, including calcium and lime scale, as well as stubborn rust stains from a variety of surfaces. It features a multi-surface application capability and is part of the professional line by Jelmar. The bottle appears to be partially used, evidenced by the smudges and exterior wear, making it a functional utility item for maintenance tasks rather than a pristine retail product. Ideal for janitorial needs, plumbing maintenance, or industrial cleaning projects where large quantities are required for effectiveness.