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. Installs easily and permanently. Made of flame-retardant black plastic with black vent head/cover. Type SS Hose 5/8" I.D. Max Hull 9/16" Hole 3/4" Pkg. Retail