These gearmotors are an inexpensive way to put your project in motion! The required voltage is 4.5-6V with a no load current of 190mA. The output shaft is 9mm long and the gearbox ratio is 48:1 with a wheel speed of 140 RPM (unloaded). These are the motors used on our popular Runt Rover Robot Kit series. Use with our 2.55” or 3.10” press-fit robot wheels.