This system holds 3.25 gallons and 2 Black Berkey water purification elements are included. Also bundled with this package are 2 PF2 filters. You can filter up to 4 gallons per hour. You can add 2 more Black Berkey elements (for a total of 4) which would allow you to purify up to 8 gallons per hour. The system is a beautiful high-grade polished 304 stainless steel that look great in every house.