Even on vacation we need a signal to recognize each other between wizards, so what better than the famous Spectrespecs of our Luna on your beach towel ! A touch of magic and sweet madness with you during the holidays.
When they arrive in 6th year, after having beautifully put Harry's nose back in place and asking her what he looks like, she answers "Exceptionally ordinary". Which looks like the character of the character !
Harry Potter official license