Attwood Marine - Fuel Tank Vent - 90-Degree Standard Mount - for 5/8" Hose - Black - 16703. 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.. Features:. Type - Black. Hose - 5/8" Inside Diameter. Max Hull Thickness - 9/16". Hole - 3/4"