Orb Tech Hart Junior Finger Cap 200ml Country of Origin: United States of America Ingredients: Phosphoric acid, Ethanol Acidity: Acidic Although strongly acidic, the main component is phosphoric acid, so it will not cause burns if it comes into direct contact with your hands. The acidic power is effective in removing soap scum, black stains, limescale, verdigris, water stains, as well as urine scale and moss, which are common water-related stains.