This part is a genuine KitchenAid part. The Internal Gear is used in all six-quart mixers and many five-quart mixers. This Gear is found in the lower portion of the Lower Gear Casing. This Gear drives the Agitator Shaft that turns the mixing attachments such as the Flat Beater. This gear should be replaced when there is significant wear or if any of the teeth have been damaged.