www.waterfilters.netPentek-CBC-5-Cyst-Reduction-Water-Filters.htmlbr The Pentek CBC-5 is a 0.5 micron carbon block designed to produce healthier, better-tasting drinking water. The Pentek CBC-5 water filters have enhanced dirt holding capacity and the filter's unique carbon block structure enables it to reduce 99.5 of Giardia, Cryptosporidium, Entamoeba, and Toxoplasma cysts and fine sediment particles down to 0.5 microns (based on manufacturer's internal testing). Also known as the Ametek CBC-5, this water filter cartridge is an ideal choice for a wide range of residential, food service, commercial and industrial applications. They also make excellent polishing filters or pre-filters in applications requiring fine filtration and high capacity.