APS117 3M Aqua-Pure Whole House Filter Replacement CartridgeThe 3M Aqua Pure APS117 water filter cartridge is for use with many 3M Aqua Pure whole house water filtration systems that use 9 3 4 inch by 2 1 2 inch water filters. Unlike the 3M Aqua Pure AP117, the APS117 also removes Scale. Whole house water filter systems are great solutions to help protect your pipes and appliances as well as offer you great tasting drinking water from anywhere in the home. Provide more pure water by ordering the Aqua Pure