Sierra 18-7721 Mercruiser Fuel Filter Replaces 35-864572Sierra replacement fuel filters are designed to meet OEM specifications. All Sierra Fuel Filters not only protect your engine, but are also over 90% efficient at removing engine damaging 10-micron and larger particles without starving the engine for fuel.This fuel filter fits Mercruiser MPI & EFI engines with boost pump, 8.1L & 496 CID for 3/8" I.D. Fuel Lines.Interchangeable with: Mallory; 9-37826; Mercruiser Stern Drive; 35-864572; 35-864572T; 35-864572T01;