Genuine OEM Volkswagen Coolant Hose, part number 2Q0121049AG. This hose transports coolant between engine components and the radiator, featuring a quick-release coupling for easier service. It is identified as item 1 in the diagram. The hose is made from durable materials designed to withstand high temperatures and pressures. Genuine OEM coolant hoses are engineered with precise dimensions and material properties to ensure optimal coolant flow and prevent leaks.