Berkey BK4X4-BB Big Berkey Stainless Steel Water Filtration System with 4 Black Filter Elements Includes one Big Berkey water purification system, and 4 self-sterilizing Black Berkey water filters Filter lifespan of 3000 gallons per filter, 6000 per set of two, or 12000 for the set of 4 Big Berkey has a 2.1 gallon capacity, produces up to 7 gallons of filtered water per hour, with 4 BF2s Housing is high grade 304 stainless steel. Each Filter is cleanable and &nbsp;self-sterilizing Removes &gt;99.999% of viruses, pathogenic bacteria, chlorine & volatile organic compounds