Watersense Certified: Rated for 1.75GPM for better water filtration. Available for sale in all States. Chlorgon filtration system helps to remove free chlorine, dirt and odors from water Includes replaceable SLC filter cartridge (rated for 6 months or 10,000 gallons - whichever comes first) Filter cartridge tested and certified to NSF/ANSI Standard No. 177 Fits most 1/2-inch NPT shower arms Both the system and installation complies with strictest state and local regulations.