Genuine OEM Audi Air Conditioning Expansion Valve, part number 4M0816181A. This essential component precisely regulates the flow of refrigerant into the evaporator, which is critical for controlling the cooling capacity of the air conditioning system. It is typically located at the inlet of the evaporator within the HVAC assembly. Constructed from durable materials, this valve measures approximately 8 cm in length and weighs 0.177 kg. Choosing a genuine OEM expansion valve ensures exact factory specifications for refrigerant flow and pressure, vital for the optimal performance and longevity of the entire AC system.