NSF Certified to reduce Lead, Chlorine, Taste and Odor. This filter is compatible with KitchenAid Refrigerator Ice and Water Filter 4 - KAD4RXD1. Note: KitchenAid Refrigerator Ice Water Filter 4 - KAD4RXD1 is not compatible with KAD1RXD1,KAD2RXD1,KAD3RXD1. For clean, fresh water, replace the Percola Filter 4 every 6 months or 300 gallons (depending on actual use). Run water from the dispenser for 5 minutes at 0.5 gpm (about 2.5 gallons) to clear the system and prevent sputtering.