The Premier 400 Timelights Christmas lights are battery operated and use warm white LEDs. They have an 8-setting multi-action controller with a built-in 6 hours on/18 hours off timer. These lights require 3 x C batteries, which are not included. They are suitable for both indoor and outdoor use, and have a lit length of 39.9m. The battery life is up to 30 days from 3 x C batteries. They are also available in white and multi-coloured.