Pentek RFC-BB # 155141 RFCBB Radial Flow Whole House GAC Carbon Big Blue Water Filter Cartridge Compatible With Culligan, Ametek, US Filter, Plymouth, Kleen Plus, American Plumber, Bruner & Many Other Brands. Radial Flow Big Blue Carbon 25 Micron Water Filter. 10" long X 4 1/2" diameter. 8 per case, sold individually. Ametek # 155141. Same as Culligan RFC-BBS. RFC Series cartridges are constructed with a porous polypropylene outer shell and durable polypropylene end caps. Sandwiched between the outer shell and the core is a bed of granular activated carbon. The unique radial flow design offers the benefit of granular activated carbon filtration, such as low pressure drop, while at the same time eliminating the release of carbon fines commonly associated with GAC style cartridges. RFC Series cartridges are ideal for point-of-entry POE, whole house filters and other high flow rate applications. Order a case and save even more.