Electrically operated submarine. The submarine is connected to a battery box and speed controller by long wires. I haven't tried it out , but I have examined it and can say that it dives by setting the manually adjustable forward diving planes to the diving position , and driving the submarine through the water with sufficient speed to overcome the buoyancy of the submarine. The submarine has 3 speeds , which are achieved by setting the dial on the battery box to numbers 1 to 3 in forward or reverse. This corresponds to supplying the motor with 1.5V from one battery ,3V from 2 batteries or 4.5V from 3. It is interesting how the maker's enclosed the motor totally in a plastic case. There isn't any mechanical link between the motor shaft and the propeller shaft , but a magnetic link. This means that water will not be able to enter the motor housing. The downside is that you can't lubricate the motor. I have taken a couple of pictures of the inside of the submarine , which can be viewed in the gallery.