90Adeg P-Trap Fuel Tank Vent - Black with Stainless Steel Trim CoverComposite 90-degree P-trap fuel tank vent 66419-3. 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. Features: For 5/8" I.D. hose (inch) 3/4" install. hole size (inch) 9/16" max. hull thickness Vents air from your boat&';s fuel tank as you fill the fuel tank Splash-resistant, corrosion resistant Meets ABYC standard *Compatible with Ethanol blended fuels Quick Guide (pdf)