Genuine OEM Audi hex nut, part number 4E0805831. This fastener is used to secure various components within the body or engine assembly, providing a reliable and vibration-resistant connection. It is marked as number 24 in the assembly diagram. The nut is manufactured to exact thread pitch and material specifications to ensure compatibility with factory studs and bolts. Using genuine OEM fasteners is essential for maintaining the structural integrity of the assembly, as they are designed to meet specific torque requirements and resist corrosion over the life of the vehicle.