The Bucket Berkey comes with two food-grade quality 5-gallon buckets, Black Berkey water filters, a spigot, and the appropriate washers and stoppers. You can select to purchase 1, 2, or 4 Black Berkey Filters under options. They Bucket Berkey is great for emergency preparation, or for use in outdoor or international locations. The Bucket Berkey is extremely portable, with one bucket fitting inside the other for easy storage or transportation. Each filter element will provide efficient water filtration between 3,400 gallons to 19,500 gallons, depending on water quality. Heavily contaminated water would result in shorter filter element use, i.e. swamp water, filthy river water or heavily chlorinated* water. Filtering cleaner water, such as clear lake or stream water, snow or rain results in longer filter use.