Walker AirSep is the closed crankcase air filtration and air/oil separation system of choice for marine diesels and gensets. It captures engine blow-by oil and gases (normally discharged into your engine room, or the environment), and reintroduces them into the engine. The result is a markedly cleaner engine room and no noticeable oil smell in the salon or cockpit. These genuine AirSep multi-ply replacement air filter elements are designed to provide the highest airflow available for today's air hungry, turbocharged diesel engines. The filters are washable, and may be cleaned 2 - 3 times using the appropriate Walker Cleaning Kit (sold separately). Direct replacement air filter for AirSep Sealing compound creates a seal between the air filter and the Airsep cannister, and allows for easier removal when air filter elements are removed for cleaning Some units have subtle differences in design; be sure to measure your old filter before ordering