Genuine OEM Volkswagen Flywheel, part number 03L105266BL. This flywheel is a heavy rotating mass that connects the engine's crankshaft to the transmission. It smooths out the power pulses from the engine and provides a friction surface for the clutch assembly. It is mounted to the end of the crankshaft. Genuine OEM flywheels are balanced to exact specifications to prevent vibration and ensure smooth operation.