The Black Berkey Primer is a manual pump that makes priming of Black Berkey filter elements easier without the need for tap pressure or when the space under the tap si too small for priming. Priming the Black Berkey purification elements is essential to expel air and saturate the filters with water before use. The Primer pump also allows you to purge the Black Berkey elements with air to clean the porous structure of the filter if necessary and to dry the filters for long-term storage (see information on storing Black Berkey filters for details). The Primer pump therefore allows you to: 1- Eliminate debris that can build up in the filter pores during use, 2- Reduce the time that is necessary to dry the filters before storage, 3- Facilitate the priming of the elements when water pressure is not accessible or when space under the tap is limited. 4- Black Berkey filters should never be primed with contaminated water. This is the case, for example, if you only have access to reclaimed water such as rainwater, borehole water, well water, etc. You must prime them with the Black Berkey Primer pump. It is an essential tool in these conditions. The Black Berkey Primer is especially designed for use with Black Berkey purification elements. Find here the Black Berkey Primer instructions for use To complement this information, you can watch a video on using the Black Berkey Primer.