Genuine OEM Volkswagen Self-Locking Nut, part number N0230037. This nut is designed to resist loosening under vibration, often featuring a nylon insert or deformed threads. It is used to securely fasten components, particularly in exhaust systems where vibration is common. The self-locking feature ensures a reliable connection, preventing premature failure and maintaining exhaust system integrity. Genuine OEM nuts provide precise threading and material strength for lasting performance.