*arabic: acbar = unequaled
Using one internal and one external gear small and medium gear reductions can be realized. In case higher gear reductions are asked two pairs of gears are necessary, consisting of internal and external gears. A design, with which the highest gear reductions are enabled, is realized withgears, when the eccentric gear of the propulsion stage is connected with the gear of the output stage. The translation formulas of such gears may vary with different forms.