Pentek R50 Pleated Polyester Filter Cartridge, 9-3/4" x 2-5/8", 50 Microns Reduces sand, dirt, silt, rust, and scale particles in residential and commercial water Nominal filtration rating of 50 microns Non-woven polyester media pleated around a polypropylene core for strength Initial pressure drop of less than 1 psi at a flow rate of 10 gpm Temperature range of 40 to 125 degrees F (4.4 to 51.7 degrees C)