The dual mass flywheel is a component which forms part of the transmission parts. It fits to the crankshaft to act as a friction surface for the clutch. The clutch and flywheel form a partnership to store energy from the car engine.
Flywheels are only present in manual vehicles, usually those with a diesel engine or petrol engines with high torque output. This part will need replacing if the surface is damaged and unable to create friction on the clutch, which could be due to wear and tear or an oil build-up.