Above Water Systems, Inc. Seagull IV X-1F and PurestOne TP-1 Compatible Replacement Cartridge The AWS-1 Replacement Filter Cartridge employs carbon block The stringent LABORATORY TESTS were specifically designed to test the ability to reduce contaminants such as Arsenic V (pentavalent arsenic) and Volatile Organic Compounds (such as chlorinated solvents, chloroform, carbon tetrachloride, dichloroethane, dichloroethylene, methylene chloride, tetrachloroethylene, trichloroethane TCE, trichloroethylene, vinyl chloride and benzene. Above Water Systems AWS-1 and AWS-2 carbon block filter formulations are tested according to NSF/ANSI Standard 42 (Aesthetic Effects) and Standard 53 (Health Effects). The AWS-1 filters are designed to be used where the water is microbiologically safe and has been adequately disinfected. Systems certified for cyst reduction may be used on disinfected water that may contain filterable cysts. The AWS-1 and AWS-2 carbon block filter formulations have been tested according to NSF/ANSI Standard 53. The concentration of the indicated substances in water entering the system was reduced to a concentration less than or equal to the permissible limit for water leaving the system. The AWS-1 and AWS-2 carbon block filter formulations have been tested according to NSF/ANSI 40 for removal of Incidental Contaminants / Emerging Compounds