Genuine OEM Audi Metering Line for Reducing Agent Injector, part number 4G0131984AK. This specialized line is responsible for accurately delivering the reducing agent (such as AdBlue) from the reservoir to the injector, which is a critical component of the vehicle's selective catalytic reduction (SCR) emissions system. Weighing 0.218 kg and approximately 0.37 m long, its precise construction and material integrity are essential for preventing leaks and ensuring the efficient operation of the emissions control system.