Pentek WP-5 String-Wound Polypropylene Filter Cartridge, 9-7/8" x 2-1/4", 5 Micron Reduces sand, silt, scale, and rust particles in residential and municipal drinking water and industrial fluid applications Nominal filtration rating of 5 microns Polypropylene cord precisely wound on a rigid core for high dirt-loading capacity Initial pressure drop of less than 2.5 psi at a flow rate of 10 gpm Temperature range of 40 to 145 degrees F (4.4 to 62.8 degrees C).