Ultra liquid sour iron remover works to remove iron and set-in rust staining. Prevents discoloring caused by high iron content in the water supply. Free of phosphates and phosphoric acid. Closed loop packaging requires P&G Professional On-Premise Laundry dispensing equipment. Super concentrated formula contains less water and requires less packaging. Application: Laundry Booster; Applicable Material: Fabric; Dirt Types: Iron; Rust; Stains; Physical Form: Liquid.