The Sport Berkey Portable Water Purifier Utilizes: IONIC ADSORPTION MICRO FILTRATION. This advanced technology was developed, refined, and proven through diligent, investigative research and testing performed by water purification specialists, researchers and engineers. The media within the filter element removes contaminants by a surface phenomenon known as "adsorption" which results from the molecular attraction of substances to the surface of the media. As the bottle is pressed, the source water is forced through the filter. The quality and volume of media used, determine the rate of adsorption. The flow rate or time of exposure through the filter has been calculated to yield the greatest volume removal of toxic chemicals caused by pollution from industry and agriculture. This exclusive filter element is impregnated with proprietary "absorbing" media that promotes IONIC "absorption" of pollutants within the micro-porous element, such as aluminum, cadmium, chromium, copper, lead, mercury, and other dangerous heavy metals.