Clutch discs are circular friction plates integral to manual transmission vehicles, positioned between the engine flywheel and pressure plate. Their primary function is to transmit engine torque to the transmission input shaft when engaged, enabling gear changes. Core construction utilizes a steel center hub splined to the input shaft, faced with friction material riveted or bonded to both sides. Dampening springs or torsional dampers are commonly incorporated to mitigate driveline vibrations and noise. Variations exist based on spline count, diameter, friction material composition, and damping technology, dictated by vehicle and transmission specifications.