Pentek WPX100BB20P String-Wound Polypropylene Filter Cartridge, 20" x 4.5", 100 Microns Reduces sand, silt, scale, and rust particles in residential and municipal drinking water and industrial fluid applications Nominal filtration rating of 100 microns Fibrillated polypropylene cord wound on a polypropylene core for strength and minimum extractables Maximum flow rate of 65 gpm Temperature range of 40 to 165 degrees F (4.4 to 74 degrees C).