by Perko. The old flying saucer looking one with a silver ring holding on the lense. I replaced the light with a blue LED and mounted it on the top of my wind generator pole. I first cut a round star board base with a holesaw and used a threaded rail mount threaded into the star board. The result was a little spaceship looking light sitting on top of my wind generator. It's nice to be able to find your boat in the dark.