2 Count, 2 Stage Under Sink Drinking Water System Replacement Cartridge, Easy Change 1/4 Turn Cartridges, .5 GPM Flow Rate, Reduces Taste, Odor & Chlorine, Reduces Particulate Class 1, Cysts, Lead, Lindane & Atrazane, Certified To NSF 42/53, For Use With Culligan #Us-2.