Complete Filter Kit – This under-sink replacement filter kit includes all necessary components to maintain your PuROTwist 4000 RO Filtration System, including a 50 GPD RO membrane for optimal performance Improved Taste – Enjoy crisp and refreshing drinking water by eliminating unpleasant tastes and odors, providing premium-quality water for your household's daily use Cost Efficiency – The PuROTwist replacement filters offer a cost-effective solution compared to bottled water, saving you money while reducing plastic waste and providing premium-quality water for drinking, cooking, and more High Rejection Rates – The PuROTwist 4000 replacement filters effectively reduce up to 98% of contaminants including chlorine, Arsenic V, lead, fluoride, sediment and more, ensuring high-quality water for your home Easy to Replace: The quick-change twist-on/off filters ensure hassle-free installation. This kit includes PuROTwist 4000 filters, membrane, and O-rings. The filters should be replaced every 12 months, and the RO membrane every 24 months This 1-year filter replacement kit for the PuROTwist 4000 RO water filter system ensures optimal performance and water quality. It includes all essential filters, a 50 GPD TFC membrane, and replacement O-rings for a complete system refresh. Includes: Stage 1: Sediment Pre-Filter (Q5605) – Replace every 6-12 months Stage 2: Carbon GAC Pre-Filter (Q5633) – Replace every 6-12 months Stage 3: RO Membrane TFC 50 GPD (TQ56-50FC) – Replace every 24 months Stage 4: Carbon GAC Post Filter (Q5633) – Replace every 6-12 months O-Rings: 4x H-118 and 4x H-011 for filter heads The PuROTwist filters feature a quick-change, twist-on/off design for easy installation. Regular filter replacements ensure clean, great-tasting water for drinking and cooking. Filter lifespan depends on water quality and usage—monitor and replace as needed to maintain peak performance.