This sickle head mounts on the cutter bar of a grain harvester header. It secures the knife section to the reciprocating drive assembly, transmitting the cutting motion from the wobble box to the blade. Wear on the mounting holes or the head body causes slop in the knife drive, leading to uneven cutting and increased vibration. The original geometry matches the hole pattern and the drive pin location so the knife register is maintained without shimming. On reinstall, ensure the retaining bolt is torqued to spec and the knife section is aligned with the ledger surfaces.