Pentek WPX100BB97P Big Blue String Wound Sediment Replacement Water Filter Cartridge Compatible With Culligan, Ametek, US Filter, Plymouth, Kleen Plus, American Plumber, Bruner & Many Other Brands. WPX100BB97P Big Blue 100 Micron Fibrillated Polypropylene String Wound Sediment Replacement Water Filter. 10" long X 4 1/2" diameter. 8 per case, sold individually. The WPX-BB Series cartridges are constructed of fibrillated polypropylene wound on a polypropylene core. The fibrillated polypropylene should be used when pressures require minimization of extractables and/or fiber migration. Super high quality replacement sediment Big Blue filters. #WPX100BB97P Order a case and save even more.