Christmas lights string by vidaXL length 40m, with 400 led lights, with a thickness of 5mm. 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 have IP44 protection, which means they cannot be penetrated by solid objects larger than one millimeter and also cannot be penetrated by water with high intensity. They allow you to choose between various lighting programs, depending on your mood.. They operate with electricity.