Osculati Marine Fuel Filter – For Diesel Engines – With Water Separator And Quick Drain – 30 Micron CartridgeThis filter and water fuel separator has a 30 micron cartridge with an aluminium head. At the bottom of the system is a quick drain bowl made from aluminium. Water in your fuel can occur over time due to condensation of moist air. The water is more dense than the fuel and so will collect at the bottom of the tank. If water is left to flow into your engine, this will result in running problems and potentially damage to your diesel engine. This combined