Hollow Fiber membrane are tiny hollow tubes that look like straws. These tubes have a porous membrane wall and works through size exclusion. Clean water is allowed to go through the membrane while larger contaminants cannot fit through the pores. Hollow Fiber blocks bacteria, E. Coli, Cholera, Typhoid, protozoa, Cryptosporidium, and parasites (Giardia). Our Hollow Fiber membrane filters down to 0.1 microns.