Christmas lights. These were purchased a few years ago from modern display. I have two 50 ft strands with 6-in spacing for C9 bulbs. One of them has all sockets in place the other one I removed some of the sockets for our roof design. I also have extra sockets and plugs so you can customize for what you need. We have since gone to permanent lighting, so we don't need these anymore. Our bulbs were red and green, but it will work with any. You are welcome to all the bulbs we have as well.