This is a common bicycle dynamo (Friction) which generates 6v 3w power. Just install this dynamo on your bicycle's right rear seat stay or right front fork. The dynamo should be located ahead of the mounting bracket. To avoid the dynamo from contacting your bicycle wheel, just press the dynamo down, then you will have faster riding speed. Use this dynamo to light up LEDs, or something else... Save energy, save the planet.