Submarines can see the surface of the ocean with a periscope when they are close to the surface.
A standard viewing device used on a submarine is a periscope.
A device for viewing microscopic things.
Periscope.
i think you mean the 'periscope'.
A periscope.
scope
The object used to view the outside from inside the submarine is called a periscope.
Asdic
Phone? Ipod? Camera? ...
Below
The Nautilus was Fulton's submarine.
A submarine is an undersea boat, or submersible.