CARBON BLOCK CARTRIDGE: The Watts Premier OneFlow Plus Radial Flow Carbon Block Cartridge is designed for chemical-free scale reduction and protection by converting hard minerals into soft particles, thereby preventing build-up inside pipes and retaining beneficial minerals like calcium, potassium, and magnesium. HIGH-CAPACITY FILTRATION: This high capacity 20-micron cartridge has a dirt holding capacity of up to 2.2 lbs. (1 kg) and removes chlorine taste and odor while reducing sediment. It provides chlorine reduction of up to 50,000 gallons (189,000 liters) at a 3 GPM (11.34 lpm) flow rate. EFFICIENT FILTRATION: This cartrdige does not add or remove anything from the water and operates without chemicals or salt, promoting sustainable water treatment and leaving only high-quality drinking water. FOR ONEFLOW PLUS: This cartridge is specifically designed for use with the Watts Premier OneFlow Plus Whole House system. We recommended replacing every 50,000 gallons or 12 months. When replacing ensure to turn off the inlet and outlet valves on the system’s supply and outlet lines. 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.