Attwood Marine Black Plastic P-Trap Fuel Tank Vent Standard Mount 5/8" I.D. Hose. These vents help prevent water from entering the fuel tank, yet allow air to vent freely, during normal sea conditions and washdowns. This eliminates the need for an anti-siphon loop in the vent hose. Meets ABYC standard. The arrows in this cross-section show the baffled route that water would have to travel in order to reach the fuel vent hose. Compatible with Ethanol blended fuels.