Pentek DGD-2501-20 Spun Polypropylene Filter Cartridge, 20" x 4-1/2" Reduces sand, silt, scale, and rust particles in residential, commercial, and municipal drinking water Combines two separate gradient layers for higher efficiency and dirt-loading capacity Spun polypropylene for resistance to chemicals and bacteria Initial pressure drop of less than 1 psi at a flow rate of 20 gpm Temperature range of 40 to 145 degrees F (4.4 to 62.8 degrees C).