Let this Christmas light set of multi-color bubble lights bring back joyful childhood memories. The 7 blue, orange, and red candelabra base bulbs are spaced 12 inches apart on 7 feet of green wire. Their warm light is created by the incandescent bulb, which also generates the heat to bubble the liquid within the tube. Always use bubbling lights in upright position. Allow several minutes for lights to heat up for the bubbling action to begin. A light tap will get any slow starters going. For over 70 years, this novel invention has graced Christmas trees, garlands, and centerpieces. UL listed for indoor/outdoor use, seven sets can be safely connected with the male to female connections.