Style: Sediment Filters X 12 + CTO Filters X 8+ RO Membrane X 1Stage 1 (FP25B): The polypropylene sediment filter removes sediments, dust, sand, large particles, silt, dirt, and rust from water, preventing clogs and pressure loss.Stage 2 & 3 (FC25B): iSpring carbon block filter removes up to 99% of chlorine as well as taste and odor compounds, pesticides, herbicides, and more.Stage 4 (MCRO1000): The 1000 GPD RO membrane removes up to 99% of over 1,000 contaminants, including lead, chlorine, fluoride, arsenic, asbestos, calcium, sodium, and more.Replace 1st stage filter every 3-6 months, 2nd stage and 3rd stage filters every 6-12 months, and replace RO membrane every 2-3 years. The filter replacement schedule depends on the source water quality.