BI-ANNUAL FILTER REPLACEMENT KIT: Say goodbye to unpleasant tastes and odors with the Watts Premier Bi-Annual RO Pure Plus 2-Pack Filter Kit, a 6-month supply for your under sink RO Pure (WP531411, WP531407) or Zero/Pure Plus (WP531517, WP531417). The included 2 filter types are tailored for specific filtration purposes, collectively ensuring crystal clear, great-tasting drinking water every time. Please note this kit will not fit the Watts 1/4 Turn Kwik-Change RO System. HIGHLY EFFECTIVE FILTRATION: This 2-pack 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) for conditioning the water and reducing chlorine taste and odors. SMART DESIGN: Each of these top-performing 11-inch filters is denoted by a different color for easy identification: red for sediment and yellow for pre-filter. They also feature 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! QUALITY CONSTRUCTION: These durable filters are crafted from high-quality materials for maximum filtration. Filter life may vary based upon local water conditions or use patterns, but we recommend replacing these sediment and carbon pre-filters every 6 months. THE PREMIER DIFFERENCE: Since our founding in 1989, Premier has been dedicated to the design, development, and marketing of high-quality water filtration systems that exceed industry standards. Following our Watts Water Technologies in 2001, our audience and influence have only expanded, solidifying Watts Premier as a trusted leader in the industry.