The Schmidling Maltmill with Adjustable Gear Drive OIption and Case Hardened Rollers is a dual roller adjustable mill that comes with the gear drive option preassembled. Includes case hardened rollers. These heavy-duty rollers are for high-volume use. Less wear than the standard rollers. Motorize your mill for the ultimate crushing experience! If you are thinking about this model because you can attach a motor to it, buy it. A gear drive cannot be added later on the other models.