1-Year Replacement Filter Kit with RO Membrane for Microline TFC-400 Reverse Osmosis System INCLUDES: * STAGE 1 - 1x 5 micron Sediment Pre-Filter (S7011) - Replace Every 12 Months * STAGE 2 - 1x Sediment/Carbon Pre-Filter (S7028) - Replace Every 12 Months * STAGE 3 - 1x RO Membrane TFC 50 GPD (S1229RS) - Replace Every 24 Months * STAGE 4 - 1x Inline Carbon GAC Post Filter (K2333-KK) - Replace Every 12 Months Filters may need to be replaced more often than indicated depending on incoming water contaminant levels and volume of water being treated.