Genuine OEM Volkswagen Dodecagonal Head Bolt, part number 03D103109C. This bolt is a specialized fastener used in engine construction, identified by its dodecagonal (12-point) head. It is marked as number 21 in the engine component diagram. Proper torque and fit are essential for the integrity and performance of the engine. Genuine OEM bolts are manufactured to precise specifications, ensuring the correct material strength and thread engagement for reliable and long-lasting engine operation.