Mighty Bright TravelFlex Book Light, Purple by Mighty Bright. $12.01. Bright LED lasts up to 100,000 hours. Offers up to 24 hours of continuous use with 1 AAA battery (included). Slim design stows almost anywhere. Clip on to maps, books or magazines. Custom engineered reflector with optical grade lens spreads light evenly without any hot spots. A thin and flexible book light that provides illumination for reading and other traveling activities.