I am using two of these beehive marker lights (9 LEDs) on back, along with a yellow strobe. They are almost painful to look at directly, and they are quite noticeable off-axis. I got mine from AutoZone or Pep Boys for about $10 each. To mount them I epoxy a bolt and the wiring pigtail on--I just duct tape around the light to make a form and fill it with a whole package of quick set epoxy glue.