Pentek CBC-20 Carbon Block Replacement Water Filter # 155309 CBC20 Compatible With Culligan / Ametek / US Filter / Plymouth / Kleen Plus / American Plumber / Bruner / Many Other Brands. Carbon Block Half Micron Water Filter. 20" long X 2 7/8" diameter. 6 per case, sold individually. Ametek # 155309 CBC Series cartridges are highly effective at reducing unwanted taste, odor, chlorine, certain VOC's and pesticides from potable drinking water. With a nominal 0.5 micron rating, they are equally effective at reducing Cryptosporidium and Giardia cysts, as well as fine sediment. They also make excellent polishing filters or pre-filters in applications requiring fine filtration and high capacity. Excellent prefilter. Order a case and save even more.