Nature Zone - Essential SaltEssential Salts replaces the natural electrolytes and minerals removed from water by the city's water treatment facilities. In the wild, water which is found in a river, or depression in a rock, contains soluble minerals. This is an essential source of trace minerals and salts (electrolytes) for animals. Your pet's good health requires these electrolyte ions from the dissolved salts.They are essential to the health of the blood, nerves, muscles, digestion and bone5 oz - UPC: 783178547132