The Authentic Black Berkey Elements BB9-2 Filters are designed for water systems, specifically compatible with Aqua Optima and FilterLogic brands. Made of stainless steel, ceramic, and steel, these filters use carbon/charcoal filtration method to remove fluoride contaminants. Suitable for both commercial and household use, each filter has a capacity of 2 liters and comes in a set of 2. With a height of 9 inches and a weight of 1.5 pounds, these Berkey filters are designed for the Aqua Optima Evolve model, providing clean and safe water for your household or business.