Pentek GAC-20BB Carbon Filter Cartridge, 20" x 4-1/2" Reduces chlorine taste and odor in residential and commercial drinking water 20-micron post filter helps reduce carbon fines and other particles GAC media with polystyrene outer casing and end caps for strength Initial pressure drop of 5.0 psi at a flow rate of 4 gpm Temperature range of 40 to 125 degrees F (4.4 to 51.7 degrees C)