Genuine OEM Audi Air Conditioning Dryer Insert, part number 4H0298403. This insert contains desiccant material that absorbs moisture from the refrigerant, preventing the formation of ice and corrosive acids within the air conditioning system. It is typically housed within the receiver dryer or accumulator of the A/C circuit. Weighing 0.099 kg, this cylindrical insert measures approximately 40 cm in length. Using a genuine OEM dryer insert ensures the correct desiccant type and capacity, vital for maintaining A/C system efficiency and preventing costly component damage.