Exceptional Filter Life This filter pack can filter up to 50,000 gallons depending on the use and feed water quality. Replace the filters every 3-6 months to achieve optimal performance. Fine PP sediment filters and premium quality CTO filters not only bring clean and refreshing water to every faucet in your home, but also help prolong the lives of your water-using appliances and protect plumbing from sediment and scale buildup. Premium Quality Material and Multi-layer Density Tech Complying strictly with FDA standard (CFR-Part 177) and tested by independent third party against NSF/ANSI standard((NSF/ANSI 42) for material safety and water quality, iSpring premium 5-micron polypropylene sediment filter (FP15B) captures dirt, sand, silt, dust, rust, and scale particles and extends the life of CTO carbon block filter. The polypropylene construction provides superior chemical resistance and is not prone to bacterial attack. Highly Activated Carbon Block CTO Filter Using high quality coconut shell carbon and highly compact fabrication tech, iSpring CTO filter(FC15B) knocks out cloudiness as well as bad tastes and odors, removes up to 99% of chlorine, and is highly effective on organic compounds like herbicides, and industrial solvents) and other contaminants like trihalomethanes. Great Compatibility This filter pack consists of two 10"x4.5"Sediment Filters(FP15B) and two 10"x4.5" CTO filters(FC15B). Official replacement filter cartridges for iSpring whole house water filtration system WGB21B. Fits standard 10" whole house water filtration systems. Individually sealed for freshness.