This drive chain transmits rotational force from the hydraulic motor to the reel shaft, synchronizing the reel's rotation with the header's forward speed. It is a roller chain assembly that engages the sprockets on the reel drive system, maintaining consistent bat speed for proper crop feeding into the auger. A worn or stretched chain causes the reel to slip or lag, leading to uneven crop pickup and increased header loss. This chain is constructed to the original pitch and link geometry, ensuring correct engagement with the existing sprocket teeth without requiring shimming or adjustment of the drive mount. When installing, verify the master link clip is seated with its closed end facing the direction of travel.