Genuine OEM Volkswagen A/C receiver drier, part number 4E0820189N. This component is essential for removing moisture and filtering impurities from the refrigerant within the air conditioning system, protecting the compressor from damage. It is located in the A/C assembly as shown in the diagram. Using a genuine OEM receiver drier ensures correct filtration capacity and system pressure regulation, which is critical for the longevity and cooling efficiency of the air conditioning system.