The Harmsco 801-20W water filter is a 20 micron highly efficient filter cartridge made of pleated Polyester-Plus filter media for low pressure drop high flow cap. The Harmsco 801-20W water filter features a Pleated design with up to 50% more surface area than competitive filters resulting in superior performance and increased contaminant removal Longer filtration runs for fewer change-outs and less maintenance Low pressure drop Thermally bonded for longer usable life FDA approved Materials - NSF 61 certified and has an Engineered media for superior performance. Specifications: Flow Rate: 4-6 GPM. pH: 3-11. Surface Area: 6 sq. ft. (approx.). Dimensions: 9-3/4 L; 2-3/4 O.D.; 1-1/16 I.D. Maximum Temperature: 140°F (60°C). The Harmsco 801-20W filter cartridge should be replaced when the filter fills up with sediment and the flow rate decreases. Temperature limits vary and depend on pressure and time under load.