The NEW 40:1Tetrix 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.