316 Stainless Steel Alloy Flush Mount Fuel Vent – Straight Vent . On the exterior, they have a smooth edge over the competition. Unlike some others, there is no protruding cap to cause damage or be damaged by hull bumps and scrapes. Cap unscrews with a hex head wrench for easy cleaning of the filter and pressure testing of the entire fuel system. These vents now include two silicone gaskets.Features: Straight Vent. Specifications: Hose Size inch: 5/8in inner diameter. Maximum Hull Thickness inch: 7/8in. Installation Hole Size inch: 1-3/8intwo silicone gaskets