These 100 x LED lights are powered by batteries, the benefit being they still work in winter or in areas which get no natural light in the day. They have a simple to operate timer, 6 hours on/18hours off, once you've pressed the button the lights will operate 6 on 18 off all the time so that you don't have to remember to turn them on & off. These lights are suitable for indoor or outdoor use & are the perfect alternative to solar or mains power lighting. 9.9M of illumination 30cm from battery pack to first bulb Required 4 x AA batteries (not included)8 functions including static Memory remembers which setting you had the lights on last Low Voltage Led's for extended battery life