The Tamiya twin-motor gearbox is a small (3-inch long) plastic gearbox. It contains two small DC motors that drive separate 3mm hexagonal output shafts. There are two ways to put the kit together: with a high-speed 58:1 gear ratio or with a slower 203:1 gear ratio. Either way, the motors provide plenty of power to drive any small device. This kit is great to use to power the Tamiya Track and Wheel Set.