7PK Filters Premier 1-Year 5-Stage Reverse Osmosis Replacement Filter Kit FEATURES two 10-Inch sediment filter, four 10-Inch carbon block filters, and one 10-Inch polishing filter KEEPS WATER FRESH - Reduces sediment, scale, rust, dirt, coarse sand, sand, fine sand, extra fine sand, silt IDEAL for a standard Reverse Osmosis Water Filtration Unit or any type of Water Filtration Unit with 10" housing FILTER LIFE 4 month or 12,000 gallons: Replace two or three times a year, depending on the water quality MEETS NSF STANDARDS and REGULATIONS FEATURES 2 Sediment filters 5 Micron 10-Inch, 4 Carbon block filters 5 Micron 10-Inch &amp; 1 Inline polishing filters 10-Inch KEEPS WATER FRESH - Reduces sediment, scale, rust, dirt, coarse sand, sand, fine sand, extra fine sand, silt IDEAL for a standard Reverse Osmosis Water Filtration Unit or any type of Water Filtration Unit with 10&#034; housing FILTER LIFE 4 month or 12,000 gallons: Replace two or three times a year, depending on the water quality MEETS NSF STANDARDS and REGULATIONS