Cim-Tek 30033 10 &mu;m Hydrosorb Element for The Cim-Tek Centurion Filter Housing Centurion Element 10 Micron Hydrosorb Element (3X the dirt-holding capacity compared to cellulose filters) Used to detect water and remove dirt, rust, etc. in gasoline, diesel, & ULSD When water is present, the filter will slow down flow dramatically indicating that there is too much water in the fuel