Getting its name from the way the gears rotate like the planets around the sun, the Planetary Gearbox is a precise, high quality gearbox with a RE-260 motor built into the gearbox itself to add to its compactness. A wide range of gear ratios can be attained, and two kinds of crank arms are supplied for a wider range of functions. Gear Ratios: 4:1 5:1 16:1 20:1 25:1 80:1 100:1 400:1 Motor: RE-260