Style: Sediment Filters X 12 + CTO Filters X 8+ RO Membrane x 1 Stage 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. Why iSpring? iSpring Water Systems LLC is a family owned company located in Georgia, USA specializing in reverse osmosis water filtration systems. With over a decade of experience, our products include top of the line residential and commercial reverse osmosis (RO) systems, whole house water systems, ultrafiltration systems, shower, faucet, and counter top filters, filter cartridges and housings, kitchen faucets and fittings. Our aim is to make high quality drinking water accessible for all households. With affordable pricing, high quality, prompt delivery, and top notch customer service, we hope to assist in bringing you great water for many years to come.