Pentek RFC20-BB Carbon Filter Cartridge, 20" x 4-1/2" Reduces chlorine taste and odor in drinking water Granular activated carbon (GAC) media with spun polypropylene core and polypropylene end caps for strength Porous polyethylene 70-micron outer shell reduces carbon fines and other particles Initial pressure drop of 0.90 psi at a flow rate of 4 gpm Temperature range of 40 to 125 degrees F (4.4 to 51.7 degrees C)