Genuine OEM Audi Secondary Air Injection Vacuum Hose, part number 4F0133771. This essential hose is responsible for transmitting vacuum pressure to the secondary air injection pump, a critical component in the vehicle's emissions control system. It ensures the precise operation of the secondary air injection system, which helps reduce harmful exhaust emissions. This hose is constructed from durable, flexible material, weighing approximately 0.1115 kg. Using a genuine OEM vacuum hose guarantees the correct material properties and precise fitment, which are vital for maintaining proper vacuum integrity and ensuring the vehicle meets emissions standards.