These do not convert electricity. They simply allow an appliance (dual-voltage if necessary), a transformer, or a converter from one country to be plugged into the wall outlet of another country. Adapters sometimes do not make an earth connection, and so may be unsafe. For UK and Hong Kong natives and visitors, you can visit page Common electrical adapters in Hong Kong and the United Kingdom for adapters available for you.
A Multi Plug socket, capable of accepting multiple plug types. Note that this type of socket does not ensure compatibility with different electrical standards.