The CLR PRO Calcium, Lime & Rust Remover is a heavy-duty acidic cleaner formulated to quickly dissolve and remove tough calcium and lime deposits, rust stains, and white mineral scale. This professional strength formula clings to surfaces and dissolves even the toughest buildup. It can be used on a variety of surfaces including concrete, brick, marble, and other masonry surfaces. The 32 oz spray bottle provides extended reach for hard to access areas. It is safe for use on acid-resistant surfaces. This product should not be used on polished stone surfaces. It is an effective cleaner for removing stubborn hard water stains and soap scum.