Genuine OEM Audi Coolant Hose with Regulator, part number 4E4121030. This essential component is responsible for carrying coolant and precisely controlling its flow within the vehicle's engine cooling system, maintaining optimal operating temperatures. It is integrated into the complex network of cooling lines. Weighing approximately 0.56 kg, this genuine OEM hose and regulator assembly guarantees correct routing geometry, material resistance to heat and pressure, and accurate regulation for reliable engine cooling performance.