Noticed these little bitty lights at the bike shop the other day. What you see is what you get: a little plastic gizmo that clamps around your handlebars. No wires, all self contained. It must run on a coin cell. Press on its back and it starts flashing. Press again and the flash cycle changes and eventually goes to full on. They are bright, but not really big enough to show you where you are going. They are more of an indicator so that other people can see you. Still, awfully small.