For use with the GRAYLA(R) GEOPRESS Water Purifier (sold separately), this GEOPRESS Replacement Purifier Cartridge lasts 350 uses, or approx. 65 gallons of water. Replaceable Cartridge for GRAYLA(R) Water Purifier (sold separately) Removes waterborne pathogens Improves water flavor, odor and clarity Treats 65 gallons (250L)Please note: Lifespan will decline when purifying water with high levels of silt, sediment or tannins. Cartridge press time increases towards the end of the cartridge lifespan. When press time reaches 25-30 seconds, the cartridge should be replaced. Cartridge continues to protect, even as press time increases Order today!