The 801-5/40 cartridge filter is a nominally rated “801 Premium” filter manufactured by Harmsco Filtration. The filter is 2.75″ in diameter and has a particle retention rating of 5 microns . The filter is 40″ in length and has NSF 61 Certified Polyester Cellulose filter media. This filter is a double open end, (DOE) configuration. Filters are bulk packed in cases of 24.