Filter Comparison: The effectiveness of Black Berkey filters is validated by more than 200 tests and analyses conducted in the United States on a wide range of contaminants Filtration Capacity: Gravity water filtration system with a capacity of 5.6 liters for continuous water supply Durable construction: Made of high quality stainless steel for reliable and durable use Complete system: Comes with two Black Berkey purification elements for optimal water filtration Portability: Compact and lightweight design allows for easy transportation when travelling and traveling The Travel Berkey is great for small families and for those with limited counter space.