WaterChef&reg; RCSF-7 Shower Filter Replacement Cartridges, 2-PACK (for SF-7C Shower Systems) Includes TWO (2) WaterChef Shower Filter Replacement Cartridges Powerful 2-Stage Filtration with ThermalGuard for Superior Chlorine Reduction Independently Tested & Certified by NSF International, Trusted Performance Low Cost per Shower - NSF Certified Capacity of 20,000 GALLONS per 2-Pack! Quick & Easy Cartridge Replacement (includes Cartridge Change Reminder Decals)