This listing is for a Genuine Parker Racor Fuel Filter/Water Separator Element, Part Number S3226P. Engineered specifically for the 400R-KW (and 400 series) filter housings, this element is a high-performance filtration solution designed to remove water and particulate matter from diesel fuel. As a 30-micron filter, it is typically used as a primary filter to protect sensitive fuel injection systems from bulk contaminants before they reach secondary, finer filtration stages.