Genuine OEM Volkswagen Nut, part number WHT010640. This nut is a fastener used to secure components within the coolant cooling system, preventing leaks and ensuring proper function. It is used on a coolant hose connection in the engine bay. The nut is made of metal and designed for corrosion resistance. Genuine OEM nuts ensure the correct thread engagement and clamping force, vital for maintaining the integrity of the cooling system and preventing coolant leaks.