Much like the 6-Stage Replacement Cartridge, the upgrade version found in the 7-Stage Replacement Cartridge takes an additional step of protection against harmful sediments. This system incorporates and targets the same initial six steps in addition to the final reverse osmosis (RO) stage. Taking action against every possible contaminant that can be found in your water supply can be a proactive way for you to manage the health and safety of your family through your vital drinking water. Maintaining your water filtration system consistently can ensure that your water supply is steadily free of impurities at all times. This 7-Stage Replacement Cartridge should be replaced every 6-8 months to ensure optimal performance and the highest quality of pure water.