AC plug.
Mood Enhancing Therapy Light It has four brightness levels, three color temperatures, and a built-in timer. This is the desktop lamp that delivers 10,000 lux of daylight spectrum light to counteract the effects of work fatigue, jet lag, and Seasonal Affected Disorder (SAD). Just 30 minutes of exposure to the light can block the release of melatonin, a sleep hormone. 11 3/4 H x 7 1/2 W x 1/2 D.