This friction disc transmits torque through a clutch or brake pack within the header driveline of a combine harvester. It sits between the driving and driven plates; its friction faces engage under spring pressure to transfer rotary motion to the header auger or reel drive, and slip under overload to protect downstream components. Wear on the disc reduces clamping force, leading to intermittent drive engagement or complete loss of power to the header. The original disc is machined to the same thickness and friction coefficient as the factory assembly, so no adjustment of the spring preload is required on replacement.