Thanks to battery power, you have maximum flexibility and can decorate to your heart's content. Enjoy enchanting light highlights in trees, shrubs, eaves, or treehouses - your possibilities are limitless. By the way, the 40 warm white LED bulbs can shine for over 400 hours on a single battery charge. You don't even have to think about turning them on and off - with the optional timer function, the lights automatically turn off after 6 hours and will shine again at the saved time the next evening. It couldn't be more convenient.