Need more speed? The NEW 40:1 and 20:1 TETRIX® MAX TorqueNADO® Motor Gearboxes give more rpm when compared to the 60:1 gearbox included with the TorqueNADO motor. These gearboxes are designed with the same 37 mm diameter as the original 60:1 gearbox, while using the same 6 mm D-shaft and alignment pins, so getting the additional speed you need is a breeze.The 40:1 gearbox provides one and a half times more rpm, equivalent to approximately 150 output rpm for the TorqueNADO, while the 20:1 gearbox provides three times more rpm, equivalent to approximately 300 output rpm. Both result in a reduction of power or torque.Comes prelubricated and includes three mounting screws.