Replacement Cartridge Filters EO4473 Environmental. Replacement Element for Part Number Environmental EO4473 Filter. 17.65" OD x 21" L 80/20 Blended FR sq ft media. Environmental is a registered trademark of the respective company. TDSF-10002230 Replacement Cartridge Filters EO4473 Environmental.Our Replacement filters Work As Good Or The Same As The OEM Filters. We guarantee their performance. Some of the filters are non stock items and cannot be returned. Please see our return policy.