Genuine OEM Volkswagen Ventilation Hose, part number 06A103474A. This hose is a component of the engine's crankcase ventilation system, responsible for removing unburned fuel and combustion byproducts (blow-by gases) from the crankcase. It routes these gases back into the intake system to be burned, reducing emissions and preventing pressure buildup. The correct material and shape are essential for efficient operation and preventing oil leaks. Genuine OEM ventilation hoses are designed to resist oil and heat exposure within the engine bay.