This flail set consists of two matched flails, one for the left side and one for the right side of the threshing unit. Each flail is mounted on the rotor drum and swings outward under centrifugal force to beat the crop material against the concave grates, separating grain from the straw walkers. The paired left and right flails work together to maintain balanced rotor loading; a worn or missing flail on one side causes uneven separation and increased vibration in the rotor assembly. The manufacturer machines the pivot bore and the striking face to the same geometry as the original assembly, so the flail swings freely without binding and contacts the concave at the correct angle. When replacing, install the left and right flails in their respective positions and torque the retaining bolts to the specified value.