This knife section mounts on the cutterbar of a grain-harvester header. It is the component that severs the crop stem against the stationary ledger plate during the cutting stroke. The three mounting holes align with the knife-back and hold the section in position with rivets or bolts. A worn or dull knife section produces ragged stubble and increases the draft force on the cutterbar drive, which can lead to accelerated wear in the wobble-box assembly. The original manufacturer machines the cutting edge to the same bevel geometry as the factory section, so the shear angle between the knife and ledger plate is preserved without field adjustment. When replacing, ensure the section sits flat against the knife-back and that all fasteners are tightened to the specified torque.