The dynohub has two terminals. You run a wire from each terminal to the headlight, and another wire from each terminal to the taillight. The wires from one terminal go to the + on the headlight and the - on the taillight; the wires from the other terminal go to the - on the headlight and the + on the taillight. The result is that the two lights flash alternately. Above 10 mph you won't notice the flashing. Below 10mph, think of it as a safety feature!