iSpring FA15US Alkaline Filter improves the pH value of the slightly acidic water that is a result of the reverse osmosis process. This filter is capable of increasing the pH value of the RO water by 0.5 to 1.2, helping to minimize any fluctuation in your body's pH. The filter also adds in healthy minerals such as ionized calcium, magnesium, sodium, and potassium ions which were removed during the water purifying process. These ions are structurally smaller molecules which help the body absorb more water and replenish lost water quickly, making the water healthier and cleaner. These minerals being restored will slightly increase the TDS value, normally between 10-20 ppm. Typically installed with RO systems to complement their filtration quality. What is included: 1x Alkaline Replacement Filter Cartridge Length: 10” x 2” Weight: 0.9 LB Compatible with most industry standard 10” reverse osmosis RO systems. All filters are tested by an independent third-party to meet NSF/ANSI standards.