0.50 micron bonded carbon block also containing a molecular sieve. NSF Approved Last Stage. Molecular Absorption Disc Media designed to absorb/adsorb heavy metals, volatile organic chemicals, dissolved organic matter, phosphates while flowing 4 gallons per minute. Fin-L-Filter 0.20 Micron bag filter (U.S. Patent). This second stage filter barrier restricts algae, Giarida Cysts, Cryptosproidium, fungus and E. coli bacteria. Whole House Filtration: Kold Ster-il can provide a constant 4+ Gpm flow rate while meeting NSF quality standards 42, 53, 53b, 61, 63.