Seadog 355210-1:Straight Gas Tank Vent, StainlessGas tank vents function to provide the needed air flow to maintain proper fuel flow while filling and during use. Vents compensate for changes in tank level due to consumption as well as temperature related expansion and contraction. Designed to prevent vacuum build up during use which can disrupt fuel delivery they also double as a pressure release valve for the gas tank. Two screens provide a barrier to keep unwanted contaminants from entering the tank. An integral 5/8″ hose barb securely connects vent hose.