FUELAB In-Line Fuel Filters keep your engine running clean. They feature male AN / 37 degree Flared fitting end caps, so you can attach them directly to other fuel system components. Also featured are machined internal radii for minimal pressure drop. The compact 818 Series Fuel Filter includes a 3 inch element. Fuelab also offers 4 types of filter elements for both the 818 Series short (3 inch) and 828 Series long (5 inch) Fuel Filter.