NSF 53 certified to reduce 99.6% of Lead, 99.99% of Cyst, 96.6% of Benzene, 98.4% of Carbofuran, 96.6% of Endrin for safer water. NSF 42 certified to reduce 97% of Chlorine, taste and odor for better tasting water. NSF 372 certified lead-free material. A Precise, leak-proof fit for your refrigerator. Designed to provide 6 months or 300 gallons of cleaner water. The twist-on-and-off design for easy replacement. Uses eco-friendly, renewable coconut shells as the raw material for a better planet.