It shows a 5-15 in the pictures, but the line claiming compatibility with multiple outlet types says "with adapters". It's hard to tell from the pictures if the 5-15 pigtail is removable and they don't mention providing any other outlet adapters or show any in the pictures, but that would have to be how they did it.
Technically the Tesla UMC is a similar product that varies its output depending on which outlet adapter you put on the end of it. (But, at 10kW max power.)