The F7-GAC 1-year filter pack comes with a total of 7 replacement filters so the filters can be changed on schedule for 1 year. 2x 5 Micron 10" Sediment Filters (1st Stage, #FP15): Removes dirt, rust, sand, and other particles. Replace approximately every 6 months.2x 5 Micron 10" Granular Activated Carbon (GAC) Filters (2nd Stage, #FG15): Absorbs chlorine, halide, organic contaminants, odors, and other impurities that contribute to bad tastes and odors. Replace approximately every 6 months.2x 5 Micron 10" CTO Carbon Block Filters (3rd Stage, #FC15): Further removes any remaining chlorine, tastes, and odors. Replace approximately every 6 months.1x Post Carbon Inline Filter (5th Stage, #FT15): Polishes the water from the tank before it is delivered to the faucet. Replace approximately every 12 months.Note: The 1-year filter supply does not come with an RO membrane, as the membrane only need to be changed every 2-3 years. To get a filter pack that includes the membrane, take a look at the 2-year F15-75 or 3-year F22-75 supply pack.This filter pack fits the iSpring RCC7, RCC7P, and most other RO systems that use standard sized filter housings including Flowmatic, PuROLine, Crystal Quest, and Apec.