A hollowing tool with a round tungsten carbide cutter on it. The tool is available with and without a handle.
This is the curved, gooseneck variant. Made for small hollow work up to about 10 cm deep. The tools can work through a very small opening. The carbide cutter that sits on it has a raised edge and can therefore cut and does not have to scrape. The steel has a black coating that protects it against rust. The carbide cutters have a particularly long tool life. If they become blunt, they can be turned and if they are turned a few times, they can be grinded with diamond, but because of the low price they usually are replaced.