Incandescent holiday light set. Features industrial grade 20 gauge wire, 16 inch lead wire,2.75-inch bulb spacing, and 3 inch end connect. Ideal for indoor or outdoor use. If one bulb burns out, the others stay lit. Replaceable fuse plug, extra bulbs, and fuse included. Uses 2.5 volt replacement bulb. UL (Underwriters' Laboratories) listed.