These are the components for a modular planetary gear system, which has only one planetary gear for each sun gear. Being that this system is modular - each module consisting of a planet holder, planetary, sun, and annular gear - it can be built upon as much as one wants. Each unit has a input-output ratio of 15/68 or 4.533 turns of the crank to every turn in output. This means that by connecting a mere 10 together, the combined ratio is 1:3,665,866 or 3,665,866 turns of the crank to one turn in output. The display model can be found under "Single Planetary Gear System (Display Model)" or thing:793603.