Adapter for using Japanese power plugs with plugs used in countries like Korea and Europe. There are two types of round plugs: a thinner C type and a thicker SE type, with two of each, for a total of 4. Use the thicker plug when the thinner plug is tilted or easily comes out. Since the voltage does not change with the conversion plug, be sure to use equipment that supports the voltage of the country you are using it in.