The SAO-24 Cartridge for Tersano SAO Dispenser is a patent-protected system. Cold water enters the cartridge, where resins remove select contaminants. The water is then ready to be infused with ozone (O3) to creates SAO. Tersano SAO-24 Cartridge offers up to 24 hours of sanitizing and 6 days of cleaning, with a cartridge life of up to 3,000 liters. *One (1) desiccant filter included (*varies based on incoming water quality and flow rate).