Christmas lights string by vidaXL length 15m, with 150 led lights. They emit cool white light, which is measured on the Kelvin scale with values from 5000K to 6800K. The tones of cool white are more blue compared to natural light. They allow you to choose between various lighting programs, depending on your mood, and control them remotely with the included remote control. Additionally, they have the ability to extend their length by connecting them to other bulbs.. They are powered by USB.