Product Description Say goodbye to unpleasant tastes and odors and say hello to fresh water with the Watts Premier RO Pure 4-Pack Filter Kit, a complete set of water filters for your under sink RO Pure (WP531411, WP531407) or Zero/Pure Plus (WP531517, WP531417). The included 3 filters and membrane are tailored for specific filtration purposes, collectively ensuring crystal clear, great-tasting drinking water every time. This comprehensive kit includes one 5-Micron Sediment Filter (WP105311) for reducing dirt, silt, and rust that affects the taste and appearance of your water; one 5-Micron Activated Carbon Pre-Filter (WP105351) and one 5-Micron Activated Carbon Post-Filter (WP105341) for conditioning the water and reducing chlorine taste and odors; one 50 GDP Semi-Permeable Membrane (WP105331) for reducing TDS and contaminants like arsenic, lead, nitrates, percolate, and copper, as well as cysts, including Giardia and Cryptosporidium. Our filters are crafted from only the highest quality materials for durability and maximum filtration. Filter life may vary based upon local water conditions or use patterns, but we recommend replacing sediment and carbon pre-filters every 6 months, the carbon post-filter once a year, and the membrane every 2 to 5 years. Refreshing hydration isn't the only thing that makes these top-performing 11-inch filters stand out; they also feature a user-friendly design, with each filter conveniently denoted by a different color for easy identification: red for sediment, yellow for pre-filter, blue for post-filter, and green for membrane. Furthermore, they are equipped with a push button release that allows for hassle-free replacement without shutting off the water source. Easily change out filters with a quick push of a button - no special tools required! Please note this kit will NOT fit the Watts 1/4 Turn Kwik-Change RO System. From the Manufacturer The Watts Premier RO Pure Replacement Water Filter Kit provides a complete replacement supply of filters for your RO Pure RO-4 reverse osmosis system. This kit includes one of the following replacement filters: • 1 of F105311- 11" Sediment Prefilter (Red) • 1 of F105351- 11" Carbon Prefilter (Orange) • 1 of F105331- 11" 50 gpd Membrane (Green) • 1 of F105341- 11" Carbon Postfilter (Blue) PLEASE READ: Watts Premier RO-Pure Filters change out at the push of a button. These filter will not fit Watts Kwik Change RO units. which requires a 1/4" Turn.