Certified to remove 99.97% cryptosporidium and giardia. Patented filter cartridge: The PUR Select water filter provides advanced filtration by not only reducing chlorine, but also reducing asbestos, atrazine (an herbicide), and 2, 4-D. The one-micron carbon filter also removes 99.97% of the microbiological cysts cryptosporidium and giardia. Great Value and Convenience: Easy-to-change replacement filter provides up to 100 gallons (2-3 months) of quality water, right from your tap. PUR water costs less per gallon than bottled water. Note: Removing a used cartridge automatically resets the Automatic Safety Monitor gauge (ASM). If your water contains high levels of sediment, the life of your filter can be reduced. It is normal for carbon dust to appear when first used. This dust is not harmful, but should be flushed from the system before drinking the water.