The multicolor solar Christmas lights are powered by solar energy; no extra utility electricity cost and no need to replace the battery. A light sensor regulates the charging of the solar string lights during the day and turns them on automatically at night. The solar Christmas lights can withstand all kinds of weather(IP65), including heavy rain and snow, making them perfect for indoor and outdoor decorations. Just hang the lights anywhere you like, set the panel somewhere it will get lots of sun, and use the stake to position it.