NSF CERTIFIED: This Refrigerator Filter Cartridge is Tested and Certified by NSF International against NSF/ANSI Standard 42 for materials and structural integrity requirements. EASY TO INSTALL: Quick to change - No tools required. For best results, its recommended you change your filter every 6 months. PREMIUM FILTRATION: Reduces Chlorine Taste & Odor, Sediment and other Impurities, Voc,THM'S.