The Black Berkey Primer is a hand-powered priming pump that allows you to prime your system’s Black Berkey Elements almost anywhere without a pressurized faucet or hose connection. Priming Black Berkey Elements saturates the filters with water prior to use, removing any pockets of air trapped inside the filters which can slow down the filters' ability to produce clean water. Black Berkey Elements must be primed before first use to insure proper operation. Easy to use—with a Black Berkey Element properly immersed in water and attached to it, the Black Berkey Primer creates a simple pressure gradient which draws water into the center of each Black Berkey Element. Once the Black Berkey Element is completely saturated with water, the water passes through the Black Berkey Primer and squirts out of the opposite end. The Black Berkey Primer can also purge, or backflush, Black Berkey Elements using air instead of water, clearing the compressed carbon filter wall of water debris that has accumulated with use and reducing the time and effort needed to dry the filters prior to storing them. For use only with Black Berkey Elements. Berkey Water Systems is the leader in gravity-fed filtration systems and trusted choice of adventurers, preppers, off-grid homesteaders and families for over 20 years. Berkey Systems were originally designed for extreme use for emergency preparedness and off-grid activities, and are also now used every day in millions of homes around the world by discerning, health conscious consumers who have declared water independence. Berkey systems provide economical, long-lasting water filtration for just pennies a gallon. No electricity, tools, or plumbing required. Berkey gravity-fed water systems are available in 7 sizes and are ideal for use at home, camping, fishing, RVing, or during unexpected emergencies and disaster scenarios. Enjoy delicious, refreshing water for just pennies per gallon.