What are the Berkey filters made of and how can they last for so long time with constant usage ? Can you please explain for me as most filters on the market don,t last as long as the Berkey filters. Thanks

MICROFILTRATION The first line of defense is that Berkey purification elements are composed of a proprietary formulation of more than six different media types, all constructed into a very compact matrix containing millions of microscopic pores. These pores are so small that they produce what we refer to as a “Tortuous Path” that pathogenic bacteria, cysts, parasites, herbicides, pesticides, organic solvents, VOC’s, detergents, cloudiness, silt, sediment and sedimentary minerals, foul tastes and odors must travel through. These paths are so small that these pollutants physically cannot pass through them and become trapped, eliminating them from your drinking water. This process is known as microfiltration. ADSORPTION Secondly, our media formulation uses unique adsorption and absorption properties. Adsorption works to create an ionic barrier similar to surface tension. This barrier is perfectly suited to the micro-porous water filter because it effectively allows the tiny pores to block water contaminants that are smaller than the pore size itself. This blocking process is how theBerkey® water filter is able to remove submicron viruses that other brands of water filters cannot, without the use of obnoxious chemicals like iodine or chlorine. Next, the heavy metals ions (mineral molecules) such as cadmium, chromium, copper, lead, mercury, aluminum, and other dangerous heavy metals are extracted from the water through an Ion exchange process where they are attracted to and transformed by electrically bonding to the media. FLOW RATE Finally, Berkey® systems are so effective at removing contaminants from water because of the extremely long “contact period”. Other filtration systems rely on water pressure that forces water molecules through the elements at 60-90 PSI. These water molecules come into contact with the filter media for a mere fraction of a second. By comparison, water molecules passing through the structure of the Black Berkey®elements are drawn gently by gravity and stay in contact with the media for a long period of time. This allows the filter media to be more efficient in capturing contaminants. This advanced technology was developed, refined, and proven through years of diligent, investigative research and testing performed by water purification specialists, researchers, and engineers. The flow rate or time of exposure through the Black Berkey® purification elements has been calculated to yield the greatest volume of removal of viruses, toxic chemicals, and bacteria.