REPLACEMENT FILTER: The Santevia Mineral Stones are a replacement filter for the Santevia Gravity Water System. | MINERALS IN EVERY GLASS: The Mineral Stones continuously release easily absorbed minerals into the water, including calcium, magnesium, phosporus and potassium to create water that?s healthier for you. Support your optimal health and love your body from the inside out with clean and mineralized water. | THE ALKALINE DIFFERENCE: Santevia water filters raise the pH of your water by up to +2.0 units creating a smooth and silky taste. By increasing the alkalinity (resistance to acid) of your water you support your body's ability to fight unhealthy acidity. | IMPROVES TASTE: Adding healthy minerals to your makes it taste fresh and delicious! | LASTS 2 YEAR: The Mineral Stones lasts for 2 years and can be boiled to refresh and keep clean.