The best transmission choice is when substantial transmission reduction is necessary. A worm gear is equivalent to a helical equipment with a throat lower to boost the outer diameter of the wheel. The throat allows the worm gear to wrap entirely all around the threads of the worm. By slicing the threads on the worm instead than the enamel, and by altering the amount of threads, diverse ratios can be accomplished with out shifting the mounting arrangement. A unique function of worm gears and worm equipment assemblies is their capability to avoid reverse rotation.