They are of Australian manufacture, about 20 inches long, and are unused in their original box.
These lights are generally hung by a ship's railings, along with ring buoys and safety gear. They are battery powered and hang upside down. When a man falls overboard a buoy light is cast over close to him. It automatically floats upright and lights up, allowing observers to keep track of the man's location as the ship turns to rescue him. Many a castaway and lost sailor in World Wars I and II owe their life to this simple device.
We have a few on hand. They are of Australian manufacture, about 20 inches long, and are unused in their original box. They still work. Just add ordinary flashlight batteries.