The NP-RFG20BB fits most 20" Big Blue Filter Housings. Ideal For Point-Of-Entry. The unique radial flow design reduces the release of carbon fines in filtered water and low pressure drop commonly associated with GAC-style cartridges, making it deal for point-of-entry (POE) and other high flow rate applications. Reduces Particulates in Water. The coconut shell granular activated carbon (GAC) filter media of Neo-Pure NP-RFG20BB cartridge effectively reduces chlorine taste and odor, sediment, scale and rust particles that may be present in your drinking water. Eco-Friendly Product. Made from earth-friendly granular activated carbon, the Neo-Pure NP-RFG20BB is perfect for the earth-conscious consumer. Flow Rate: 6 gpm Eco-friendly Diameter: 4-1/2" Length: 20" Filter Capacity: 40,000 gallons Micron Rating: 25 micron The Neo-Pure NP-RFG20BB 20" BB Radial Flow GAC Carbon Filter 25 micron is an excellent solution for your whole house POE (point-of-entry) water filtration needs.