Clip on light thing probably, but make sure it's one that focuses the light onto tour reader, so light doesn't wake dd up. Review them on amazon before shopping around. I was sooo pissed off when Amazon came up with the paperwhite not long after being bought the previous Kindle (hence have been through the 'what light?' review). Oh and clip needs to fit your reader snugly so doesn't boing off, fall off or shift about.