When switched on, it illuminates the deck well and the navigation light is clearly visible. Defects. It disassembles and opens easily during navigation. Bad quality plastics. that get worse with the heat of the sun. By rearranging the plastic light stop, which had opened, its tiny tooth broke as if it were a practically new Chinese toy, one of the 2 teeth that tried to fix it. I now send report to the dealer, but really a shack.