This is a kimono with a traditional fox mask also known as a kitsune mask. This set is normal something that the Japanese would wear to a festival.In a lot of things such as anime or a Japanese show if someone is wearing a fox mask they are most likely to be a sneaky thief or an assassin.
I think you're missing a word in the title. Also note that we discourage image-only posts. You might want to explain the set a little better, since I have no clue what it is.