Genuine OEM Volkswagen Cooling System Plug, part number 5B0121099. This small but crucial component is designed to seal specific openings within the engine's cooling system, preventing coolant leaks and maintaining the necessary system pressure. It is typically found in various hose connections or component ports. Weighing only 0.01 kg, this plug ensures a tight and reliable seal. Using a genuine OEM cooling system plug guarantees the correct material composition and dimensions for a leak-free and durable seal, crucial for preventing engine overheating.