You can check out this thread for more info on them.
Miboxer C4-12 thread
They come with US plug and EU plug. I’m not sure what plug they use in Australia. The power supply brick takes 100 to 240 volt and it’s a common computer style plug. I don’t see any on sale right now. One store on Aliexpress had them for $30 on 11/11, but right now they are regular price.