The Attwood P-trap has been tested and certified to meet ABYC weathertight and watertight requirements and ensures no liquid water will reach a fuel vent line, carbon canister, or fuel tank. The P-trap allows air to vent freely during normal sea conditions and wash-downs and meets the ISO 10088 requirement for minimum venting area. Cover can be removed for vent inspection, debris removal, and fuel system pressure testing. For 5/8" I.D. hose. Two-year warranty.