This 23% hydrochloric acid toilet bowl cleaner was carefully formulated with added detergents, to ensure it will work quickly and remove even the most stubborn rust, scale and mineral deposits. Ideal for hard water areas. It cleans and descales in one easy step. Application: Toilet Bowl Cleaner; Applicable Material: Toilets; Urinals; Chemical Compound: Hydrochloric Acid; Dirt Types: Mineral Deposits; Rust; Scale.