Check the listing for details. H2out Fuel Guard. Color: Blue, Condition: New. Listed at 89.95 USD. H2out Fuel Guards prevent moisture from entering the fuel tank of boats, eliminating condensation, sludge build-up, and plugged fuel injectors. The H2out Fuel Guard installs on your existing 5/8 inch fuel tank air vent line, protecting engines and fuel tanks from water vapor. The H2out Fuel Guard is the winner of the 2013 Sail Magazine Freeman K. Pittman award, Practical Sailor Best Choice award, and is used and recommended by Nigel Calder. The Fuel Guard AVD-2 is recommended for fuel tanks of 70 gallons and smaller. This comes with a standard 5/8 inch hose fitting. If you have a 3/4 or 1 inch, please let us know on your order.H2out Fuel Guards prevent moisture from entering the fuel tank of boats, eliminating condensation, sludge build-up, and plugged fuel injectors. The H2out Fuel Guard installs on your existing 5/8 inch fuel tank air vent line, protecting engines and fuel tanks from water vapor. The H2out Fuel Guard is the winner of the 2013 Sail Magazine Freeman K. Pittman award, Practical Sailor Best Choice award, and is used and recommended by Nigel Calder. The Fuel Guard AVD-2 is recommended for fuel tanks of 70 gallons and smaller. This comes with a standard 5/8 inch hose fitting. If you have a 3/4 or 1 inch, please let us know on your order.